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llvm-mirror/lib/CodeGen/RegAlloc/PhyRegAlloc.cpp
Alkis Evlogimenos 29127b8825 Change interface of MachineOperand as follows: 
a) remove opIsUse(), opIsDefOnly(), opIsDefAndUse()
    b) add isUse(), isDef()
    c) rename opHiBits32() to isHiBits32(),
              opLoBits32() to isLoBits32(),
              opHiBits64() to isHiBits64(),
              opLoBits64() to isLoBits64().

This results to much more readable code, for example compare
"op.opIsDef() || op.opIsDefAndUse()" to "op.isDef()" a pattern used
very often in the code.

llvm-svn: 10461
2003-12-14 13:24:17 +00:00

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//===-- PhyRegAlloc.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.
//
//===----------------------------------------------------------------------===//
//
// Traditional graph-coloring global register allocator currently used
// by the SPARC back-end.
//
// NOTE: This register allocator has some special support
// for the Reoptimizer, such as not saving some registers on calls to
// the first-level instrumentation function.
//
// NOTE 2: This register allocator can save its state in a global
// variable in the module it's working on. This feature is not
// thread-safe; if you have doubts, leave it turned off.
//
//===----------------------------------------------------------------------===//
#include "AllocInfo.h"
#include "IGNode.h"
#include "PhyRegAlloc.h"
#include "RegAllocCommon.h"
#include "RegClass.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iOther.h"
#include "llvm/Module.h"
#include "llvm/Type.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/CodeGen/FunctionLiveVarInfo.h"
#include "llvm/CodeGen/InstrSelection.h"
#include "llvm/CodeGen/MachineCodeForInstruction.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineInstrAnnot.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "Support/CommandLine.h"
#include "Support/SetOperations.h"
#include "Support/STLExtras.h"
#include <cmath>
namespace llvm {
RegAllocDebugLevel_t DEBUG_RA;
/// The reoptimizer wants to be able to grovel through the register
/// allocator's state after it has done its job. This is a hack.
///
PhyRegAlloc::SavedStateMapTy ExportedFnAllocState;
const bool SaveStateToModule = true;
static cl::opt<RegAllocDebugLevel_t, true>
DRA_opt("dregalloc", cl::Hidden, cl::location(DEBUG_RA),
cl::desc("enable register allocation debugging information"),
cl::values(
clEnumValN(RA_DEBUG_None , "n", "disable debug output"),
clEnumValN(RA_DEBUG_Results, "y", "debug output for allocation results"),
clEnumValN(RA_DEBUG_Coloring, "c", "debug output for graph coloring step"),
clEnumValN(RA_DEBUG_Interference,"ig","debug output for interference graphs"),
clEnumValN(RA_DEBUG_LiveRanges , "lr","debug output for live ranges"),
clEnumValN(RA_DEBUG_Verbose, "v", "extra debug output"),
0));
static cl::opt<bool>
SaveRegAllocState("save-ra-state", cl::Hidden,
cl::desc("write reg. allocator state into module"));
FunctionPass *getRegisterAllocator(TargetMachine &T) {
return new PhyRegAlloc (T);
}
void PhyRegAlloc::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LoopInfo> ();
AU.addRequired<FunctionLiveVarInfo> ();
}
/// Initialize interference graphs (one in each reg class) and IGNodeLists
/// (one in each IG). The actual nodes will be pushed later.
///
void PhyRegAlloc::createIGNodeListsAndIGs() {
if (DEBUG_RA >= RA_DEBUG_LiveRanges) std::cerr << "Creating LR lists ...\n";
LiveRangeMapType::const_iterator HMI = LRI->getLiveRangeMap()->begin();
LiveRangeMapType::const_iterator HMIEnd = LRI->getLiveRangeMap()->end();
for (; HMI != HMIEnd ; ++HMI ) {
if (HMI->first) {
LiveRange *L = HMI->second; // get the LiveRange
if (!L) {
if (DEBUG_RA)
std::cerr << "\n**** ?!?WARNING: NULL LIVE RANGE FOUND FOR: "
<< RAV(HMI->first) << "****\n";
continue;
}
// if the Value * is not null, and LR is not yet written to the IGNodeList
if (!(L->getUserIGNode()) ) {
RegClass *const RC = // RegClass of first value in the LR
RegClassList[ L->getRegClassID() ];
RC->addLRToIG(L); // add this LR to an IG
}
}
}
// init RegClassList
for ( unsigned rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[rc]->createInterferenceGraph();
if (DEBUG_RA >= RA_DEBUG_LiveRanges) std::cerr << "LRLists Created!\n";
}
/// Add all interferences for a given instruction. Interference occurs only
/// if the LR of Def (Inst or Arg) is of the same reg class as that of live
/// var. The live var passed to this function is the LVset AFTER the
/// instruction.
///
void PhyRegAlloc::addInterference(const Value *Def, const ValueSet *LVSet,
bool isCallInst) {
ValueSet::const_iterator LIt = LVSet->begin();
// get the live range of instruction
const LiveRange *const LROfDef = LRI->getLiveRangeForValue( Def );
IGNode *const IGNodeOfDef = LROfDef->getUserIGNode();
assert( IGNodeOfDef );
RegClass *const RCOfDef = LROfDef->getRegClass();
// for each live var in live variable set
for ( ; LIt != LVSet->end(); ++LIt) {
if (DEBUG_RA >= RA_DEBUG_Verbose)
std::cerr << "< Def=" << RAV(Def) << ", Lvar=" << RAV(*LIt) << "> ";
// get the live range corresponding to live var
LiveRange *LROfVar = LRI->getLiveRangeForValue(*LIt);
// LROfVar can be null if it is a const since a const
// doesn't have a dominating def - see Assumptions above
if (LROfVar)
if (LROfDef != LROfVar) // do not set interf for same LR
if (RCOfDef == LROfVar->getRegClass()) // 2 reg classes are the same
RCOfDef->setInterference( LROfDef, LROfVar);
}
}
/// For a call instruction, this method sets the CallInterference flag in
/// the LR of each variable live in the Live Variable Set live after the
/// call instruction (except the return value of the call instruction - since
/// the return value does not interfere with that call itself).
///
void PhyRegAlloc::setCallInterferences(const MachineInstr *MInst,
const ValueSet *LVSetAft) {
if (DEBUG_RA >= RA_DEBUG_Interference)
std::cerr << "\n For call inst: " << *MInst;
// for each live var in live variable set after machine inst
for (ValueSet::const_iterator LIt = LVSetAft->begin(), LEnd = LVSetAft->end();
LIt != LEnd; ++LIt) {
// get the live range corresponding to live var
LiveRange *const LR = LRI->getLiveRangeForValue(*LIt );
// LR can be null if it is a const since a const
// doesn't have a dominating def - see Assumptions above
if (LR ) {
if (DEBUG_RA >= RA_DEBUG_Interference) {
std::cerr << "\n\tLR after Call: ";
printSet(*LR);
}
LR->setCallInterference();
if (DEBUG_RA >= RA_DEBUG_Interference) {
std::cerr << "\n ++After adding call interference for LR: " ;
printSet(*LR);
}
}
}
// Now find the LR of the return value of the call
// We do this because, we look at the LV set *after* the instruction
// to determine, which LRs must be saved across calls. The return value
// of the call is live in this set - but it does not interfere with call
// (i.e., we can allocate a volatile register to the return value)
CallArgsDescriptor* argDesc = CallArgsDescriptor::get(MInst);
if (const Value *RetVal = argDesc->getReturnValue()) {
LiveRange *RetValLR = LRI->getLiveRangeForValue( RetVal );
assert( RetValLR && "No LR for RetValue of call");
RetValLR->clearCallInterference();
}
// If the CALL is an indirect call, find the LR of the function pointer.
// That has a call interference because it conflicts with outgoing args.
if (const Value *AddrVal = argDesc->getIndirectFuncPtr()) {
LiveRange *AddrValLR = LRI->getLiveRangeForValue( AddrVal );
assert( AddrValLR && "No LR for indirect addr val of call");
AddrValLR->setCallInterference();
}
}
/// Create interferences in the IG of each RegClass, and calculate the spill
/// cost of each Live Range (it is done in this method to save another pass
/// over the code).
///
void PhyRegAlloc::buildInterferenceGraphs() {
if (DEBUG_RA >= RA_DEBUG_Interference)
std::cerr << "Creating interference graphs ...\n";
unsigned BBLoopDepthCost;
for (MachineFunction::iterator BBI = MF->begin(), BBE = MF->end();
BBI != BBE; ++BBI) {
const MachineBasicBlock &MBB = *BBI;
const BasicBlock *BB = MBB.getBasicBlock();
// find the 10^(loop_depth) of this BB
BBLoopDepthCost = (unsigned)pow(10.0, LoopDepthCalc->getLoopDepth(BB));
// get the iterator for machine instructions
MachineBasicBlock::const_iterator MII = MBB.begin();
// iterate over all the machine instructions in BB
for ( ; MII != MBB.end(); ++MII) {
const MachineInstr *MInst = *MII;
// get the LV set after the instruction
const ValueSet &LVSetAI = LVI->getLiveVarSetAfterMInst(MInst, BB);
bool isCallInst = TM.getInstrInfo().isCall(MInst->getOpCode());
if (isCallInst) {
// set the isCallInterference flag of each live range which extends
// across this call instruction. This information is used by graph
// coloring algorithm to avoid allocating volatile colors to live ranges
// that span across calls (since they have to be saved/restored)
setCallInterferences(MInst, &LVSetAI);
}
// iterate over all MI operands to find defs
for (MachineInstr::const_val_op_iterator OpI = MInst->begin(),
OpE = MInst->end(); OpI != OpE; ++OpI) {
if (OpI.isDef()) // create a new LR since def
addInterference(*OpI, &LVSetAI, isCallInst);
// Calculate the spill cost of each live range
LiveRange *LR = LRI->getLiveRangeForValue(*OpI);
if (LR) LR->addSpillCost(BBLoopDepthCost);
}
// Mark all operands of pseudo-instructions as interfering with one
// another. This must be done because pseudo-instructions may be
// expanded to multiple instructions by the assembler, so all the
// operands must get distinct registers.
if (TM.getInstrInfo().isPseudoInstr(MInst->getOpCode()))
addInterf4PseudoInstr(MInst);
// Also add interference for any implicit definitions in a machine
// instr (currently, only calls have this).
unsigned NumOfImpRefs = MInst->getNumImplicitRefs();
for (unsigned z=0; z < NumOfImpRefs; z++)
if (MInst->getImplicitOp(z).isDef())
addInterference( MInst->getImplicitRef(z), &LVSetAI, isCallInst );
} // for all machine instructions in BB
} // for all BBs in function
// add interferences for function arguments. Since there are no explicit
// defs in the function for args, we have to add them manually
addInterferencesForArgs();
if (DEBUG_RA >= RA_DEBUG_Interference)
std::cerr << "Interference graphs calculated!\n";
}
/// Mark all operands of the given MachineInstr as interfering with one
/// another.
///
void PhyRegAlloc::addInterf4PseudoInstr(const MachineInstr *MInst) {
bool setInterf = false;
// iterate over MI operands to find defs
for (MachineInstr::const_val_op_iterator It1 = MInst->begin(),
ItE = MInst->end(); It1 != ItE; ++It1) {
const LiveRange *LROfOp1 = LRI->getLiveRangeForValue(*It1);
assert((LROfOp1 || It1.isDef()) && "No LR for Def in PSEUDO insruction");
MachineInstr::const_val_op_iterator It2 = It1;
for (++It2; It2 != ItE; ++It2) {
const LiveRange *LROfOp2 = LRI->getLiveRangeForValue(*It2);
if (LROfOp2) {
RegClass *RCOfOp1 = LROfOp1->getRegClass();
RegClass *RCOfOp2 = LROfOp2->getRegClass();
if (RCOfOp1 == RCOfOp2 ){
RCOfOp1->setInterference( LROfOp1, LROfOp2 );
setInterf = true;
}
} // if Op2 has a LR
} // for all other defs in machine instr
} // for all operands in an instruction
if (!setInterf && MInst->getNumOperands() > 2) {
std::cerr << "\nInterf not set for any operand in pseudo instr:\n";
std::cerr << *MInst;
assert(0 && "Interf not set for pseudo instr with > 2 operands" );
}
}
/// Add interferences for incoming arguments to a function.
///
void PhyRegAlloc::addInterferencesForArgs() {
// get the InSet of root BB
const ValueSet &InSet = LVI->getInSetOfBB(&Fn->front());
for (Function::const_aiterator AI = Fn->abegin(); AI != Fn->aend(); ++AI) {
// add interferences between args and LVars at start
addInterference(AI, &InSet, false);
if (DEBUG_RA >= RA_DEBUG_Interference)
std::cerr << " - %% adding interference for argument " << RAV(AI) << "\n";
}
}
/// The following are utility functions used solely by updateMachineCode and
/// the functions that it calls. They should probably be folded back into
/// updateMachineCode at some point.
///
// used by: updateMachineCode (1 time), PrependInstructions (1 time)
inline void InsertBefore(MachineInstr* newMI, MachineBasicBlock& MBB,
MachineBasicBlock::iterator& MII) {
MII = MBB.insert(MII, newMI);
++MII;
}
// used by: AppendInstructions (1 time)
inline void InsertAfter(MachineInstr* newMI, MachineBasicBlock& MBB,
MachineBasicBlock::iterator& MII) {
++MII; // insert before the next instruction
MII = MBB.insert(MII, newMI);
}
// used by: updateMachineCode (1 time)
inline void DeleteInstruction(MachineBasicBlock& MBB,
MachineBasicBlock::iterator& MII) {
MII = MBB.erase(MII);
}
// used by: updateMachineCode (1 time)
inline void SubstituteInPlace(MachineInstr* newMI, MachineBasicBlock& MBB,
MachineBasicBlock::iterator MII) {
*MII = newMI;
}
// used by: updateMachineCode (2 times)
inline void PrependInstructions(std::vector<MachineInstr *> &IBef,
MachineBasicBlock& MBB,
MachineBasicBlock::iterator& MII,
const std::string& msg) {
if (!IBef.empty()) {
MachineInstr* OrigMI = *MII;
std::vector<MachineInstr *>::iterator AdIt;
for (AdIt = IBef.begin(); AdIt != IBef.end() ; ++AdIt) {
if (DEBUG_RA) {
if (OrigMI) std::cerr << "For MInst:\n " << *OrigMI;
std::cerr << msg << "PREPENDed instr:\n " << **AdIt << "\n";
}
InsertBefore(*AdIt, MBB, MII);
}
}
}
// used by: updateMachineCode (1 time)
inline void AppendInstructions(std::vector<MachineInstr *> &IAft,
MachineBasicBlock& MBB,
MachineBasicBlock::iterator& MII,
const std::string& msg) {
if (!IAft.empty()) {
MachineInstr* OrigMI = *MII;
std::vector<MachineInstr *>::iterator AdIt;
for ( AdIt = IAft.begin(); AdIt != IAft.end() ; ++AdIt ) {
if (DEBUG_RA) {
if (OrigMI) std::cerr << "For MInst:\n " << *OrigMI;
std::cerr << msg << "APPENDed instr:\n " << **AdIt << "\n";
}
InsertAfter(*AdIt, MBB, MII);
}
}
}
/// Set the registers for operands in the given MachineInstr, if a register was
/// successfully allocated. Return true if any of its operands has been marked
/// for spill.
///
bool PhyRegAlloc::markAllocatedRegs(MachineInstr* MInst)
{
bool instrNeedsSpills = false;
// First, set the registers for operands in the machine instruction
// if a register was successfully allocated. Do this first because we
// will need to know which registers are already used by this instr'n.
for (unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
MachineOperand& Op = MInst->getOperand(OpNum);
if (Op.getType() == MachineOperand::MO_VirtualRegister ||
Op.getType() == MachineOperand::MO_CCRegister) {
const Value *const Val = Op.getVRegValue();
if (const LiveRange* LR = LRI->getLiveRangeForValue(Val)) {
// Remember if any operand needs spilling
instrNeedsSpills |= LR->isMarkedForSpill();
// An operand may have a color whether or not it needs spilling
if (LR->hasColor())
MInst->SetRegForOperand(OpNum,
MRI.getUnifiedRegNum(LR->getRegClassID(),
LR->getColor()));
}
}
} // for each operand
return instrNeedsSpills;
}
/// Mark allocated registers (using markAllocatedRegs()) on the instruction
/// that MII points to. Then, if it's a call instruction, insert caller-saving
/// code before and after it. Finally, insert spill code before and after it,
/// using insertCode4SpilledLR().
///
void PhyRegAlloc::updateInstruction(MachineBasicBlock::iterator& MII,
MachineBasicBlock &MBB) {
MachineInstr* MInst = *MII;
unsigned Opcode = MInst->getOpCode();
// Reset tmp stack positions so they can be reused for each machine instr.
MF->getInfo()->popAllTempValues();
// Mark the operands for which regs have been allocated.
bool instrNeedsSpills = markAllocatedRegs(*MII);
#ifndef NDEBUG
// Mark that the operands have been updated. Later,
// setRelRegsUsedByThisInst() is called to find registers used by each
// MachineInst, and it should not be used for an instruction until
// this is done. This flag just serves as a sanity check.
OperandsColoredMap[MInst] = true;
#endif
// Now insert caller-saving code before/after the call.
// Do this before inserting spill code since some registers must be
// used by save/restore and spill code should not use those registers.
if (TM.getInstrInfo().isCall(Opcode)) {
AddedInstrns &AI = AddedInstrMap[MInst];
insertCallerSavingCode(AI.InstrnsBefore, AI.InstrnsAfter, MInst,
MBB.getBasicBlock());
}
// Now insert spill code for remaining operands not allocated to
// registers. This must be done even for call return instructions
// since those are not handled by the special code above.
if (instrNeedsSpills)
for (unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
MachineOperand& Op = MInst->getOperand(OpNum);
if (Op.getType() == MachineOperand::MO_VirtualRegister ||
Op.getType() == MachineOperand::MO_CCRegister) {
const Value* Val = Op.getVRegValue();
if (const LiveRange *LR = LRI->getLiveRangeForValue(Val))
if (LR->isMarkedForSpill())
insertCode4SpilledLR(LR, MII, MBB, OpNum);
}
} // for each operand
}
/// Iterate over all the MachineBasicBlocks in the current function and set
/// the allocated registers for each instruction (using updateInstruction()),
/// after register allocation is complete. Then move code out of delay slots.
///
void PhyRegAlloc::updateMachineCode()
{
// Insert any instructions needed at method entry
MachineBasicBlock::iterator MII = MF->front().begin();
PrependInstructions(AddedInstrAtEntry.InstrnsBefore, MF->front(), MII,
"At function entry: \n");
assert(AddedInstrAtEntry.InstrnsAfter.empty() &&
"InstrsAfter should be unnecessary since we are just inserting at "
"the function entry point here.");
for (MachineFunction::iterator BBI = MF->begin(), BBE = MF->end();
BBI != BBE; ++BBI) {
MachineBasicBlock &MBB = *BBI;
// Iterate over all machine instructions in BB and mark operands with
// their assigned registers or insert spill code, as appropriate.
// Also, fix operands of call/return instructions.
for (MachineBasicBlock::iterator MII = MBB.begin(); MII != MBB.end(); ++MII)
if (! TM.getInstrInfo().isDummyPhiInstr((*MII)->getOpCode()))
updateInstruction(MII, MBB);
// Now, move code out of delay slots of branches and returns if needed.
// (Also, move "after" code from calls to the last delay slot instruction.)
// Moving code out of delay slots is needed in 2 situations:
// (1) If this is a branch and it needs instructions inserted after it,
// move any existing instructions out of the delay slot so that the
// instructions can go into the delay slot. This only supports the
// case that #instrsAfter <= #delay slots.
//
// (2) If any instruction in the delay slot needs
// instructions inserted, move it out of the delay slot and before the
// branch because putting code before or after it would be VERY BAD!
//
// If the annul bit of the branch is set, neither of these is legal!
// If so, we need to handle spill differently but annulling is not yet used.
for (MachineBasicBlock::iterator MII = MBB.begin();
MII != MBB.end(); ++MII)
if (unsigned delaySlots =
TM.getInstrInfo().getNumDelaySlots((*MII)->getOpCode())) {
MachineInstr *MInst = *MII, *DelaySlotMI = *(MII+1);
// Check the 2 conditions above:
// (1) Does a branch need instructions added after it?
// (2) O/w does delay slot instr. need instrns before or after?
bool isBranch = (TM.getInstrInfo().isBranch(MInst->getOpCode()) ||
TM.getInstrInfo().isReturn(MInst->getOpCode()));
bool cond1 = (isBranch &&
AddedInstrMap.count(MInst) &&
AddedInstrMap[MInst].InstrnsAfter.size() > 0);
bool cond2 = (AddedInstrMap.count(DelaySlotMI) &&
(AddedInstrMap[DelaySlotMI].InstrnsBefore.size() > 0 ||
AddedInstrMap[DelaySlotMI].InstrnsAfter.size() > 0));
if (cond1 || cond2) {
assert((MInst->getOpCodeFlags() & AnnulFlag) == 0 &&
"FIXME: Moving an annulled delay slot instruction!");
assert(delaySlots==1 &&
"InsertBefore does not yet handle >1 delay slots!");
InsertBefore(DelaySlotMI, MBB, MII); // MII pts back to branch
// In case (1), delete it and don't replace with anything!
// Otherwise (i.e., case (2) only) replace it with a NOP.
if (cond1) {
DeleteInstruction(MBB, ++MII); // MII now points to next inst.
--MII; // reset MII for ++MII of loop
}
else
SubstituteInPlace(BuildMI(TM.getInstrInfo().getNOPOpCode(),1),
MBB, MII+1); // replace with NOP
if (DEBUG_RA) {
std::cerr << "\nRegAlloc: Moved instr. with added code: "
<< *DelaySlotMI
<< " out of delay slots of instr: " << *MInst;
}
}
else
// For non-branch instr with delay slots (probably a call), move
// InstrAfter to the instr. in the last delay slot.
move2DelayedInstr(*MII, *(MII+delaySlots));
}
// Finally iterate over all instructions in BB and insert before/after
for (MachineBasicBlock::iterator MII=MBB.begin(); MII != MBB.end(); ++MII) {
MachineInstr *MInst = *MII;
// do not process Phis
if (TM.getInstrInfo().isDummyPhiInstr(MInst->getOpCode()))
continue;
// if there are any added instructions...
if (AddedInstrMap.count(MInst)) {
AddedInstrns &CallAI = AddedInstrMap[MInst];
#ifndef NDEBUG
bool isBranch = (TM.getInstrInfo().isBranch(MInst->getOpCode()) ||
TM.getInstrInfo().isReturn(MInst->getOpCode()));
assert((!isBranch ||
AddedInstrMap[MInst].InstrnsAfter.size() <=
TM.getInstrInfo().getNumDelaySlots(MInst->getOpCode())) &&
"Cannot put more than #delaySlots instrns after "
"branch or return! Need to handle temps differently.");
#endif
#ifndef NDEBUG
// Temporary sanity checking code to detect whether the same machine
// instruction is ever inserted twice before/after a call.
// I suspect this is happening but am not sure. --Vikram, 7/1/03.
std::set<const MachineInstr*> instrsSeen;
for (int i = 0, N = CallAI.InstrnsBefore.size(); i < N; ++i) {
assert(instrsSeen.count(CallAI.InstrnsBefore[i]) == 0 &&
"Duplicate machine instruction in InstrnsBefore!");
instrsSeen.insert(CallAI.InstrnsBefore[i]);
}
for (int i = 0, N = CallAI.InstrnsAfter.size(); i < N; ++i) {
assert(instrsSeen.count(CallAI.InstrnsAfter[i]) == 0 &&
"Duplicate machine instruction in InstrnsBefore/After!");
instrsSeen.insert(CallAI.InstrnsAfter[i]);
}
#endif
// Now add the instructions before/after this MI.
// We do this here to ensure that spill for an instruction is inserted
// as close as possible to an instruction (see above insertCode4Spill)
if (! CallAI.InstrnsBefore.empty())
PrependInstructions(CallAI.InstrnsBefore, MBB, MII,"");
if (! CallAI.InstrnsAfter.empty())
AppendInstructions(CallAI.InstrnsAfter, MBB, MII,"");
} // if there are any added instructions
} // for each machine instruction
}
}
/// Insert spill code for AN operand whose LR was spilled. May be called
/// repeatedly for a single MachineInstr if it has many spilled operands. On
/// each call, it finds a register which is not live at that instruction and
/// also which is not used by other spilled operands of the same
/// instruction. Then it uses this register temporarily to accommodate the
/// spilled value.
///
void PhyRegAlloc::insertCode4SpilledLR(const LiveRange *LR,
MachineBasicBlock::iterator& MII,
MachineBasicBlock &MBB,
const unsigned OpNum) {
MachineInstr *MInst = *MII;
const BasicBlock *BB = MBB.getBasicBlock();
assert((! TM.getInstrInfo().isCall(MInst->getOpCode()) || OpNum == 0) &&
"Outgoing arg of a call must be handled elsewhere (func arg ok)");
assert(! TM.getInstrInfo().isReturn(MInst->getOpCode()) &&
"Return value of a ret must be handled elsewhere");
MachineOperand& Op = MInst->getOperand(OpNum);
bool isDef = Op.isDef();
bool isUse = Op.isUse();
unsigned RegType = MRI.getRegTypeForLR(LR);
int SpillOff = LR->getSpillOffFromFP();
RegClass *RC = LR->getRegClass();
// Get the live-variable set to find registers free before this instr.
const ValueSet &LVSetBef = LVI->getLiveVarSetBeforeMInst(MInst, BB);
#ifndef NDEBUG
// If this instr. is in the delay slot of a branch or return, we need to
// include all live variables before that branch or return -- we don't want to
// trample those! Verify that the set is included in the LV set before MInst.
if (MII != MBB.begin()) {
MachineInstr *PredMI = *(MII-1);
if (unsigned DS = TM.getInstrInfo().getNumDelaySlots(PredMI->getOpCode()))
assert(set_difference(LVI->getLiveVarSetBeforeMInst(PredMI), LVSetBef)
.empty() && "Live-var set before branch should be included in "
"live-var set of each delay slot instruction!");
}
#endif
MF->getInfo()->pushTempValue(MRI.getSpilledRegSize(RegType));
std::vector<MachineInstr*> MIBef, MIAft;
std::vector<MachineInstr*> AdIMid;
// Choose a register to hold the spilled value, if one was not preallocated.
// This may insert code before and after MInst to free up the value. If so,
// this code should be first/last in the spill sequence before/after MInst.
int TmpRegU=(LR->hasColor()
? MRI.getUnifiedRegNum(LR->getRegClassID(),LR->getColor())
: getUsableUniRegAtMI(RegType, &LVSetBef, MInst, MIBef,MIAft));
// Set the operand first so that it this register does not get used
// as a scratch register for later calls to getUsableUniRegAtMI below
MInst->SetRegForOperand(OpNum, TmpRegU);
// get the added instructions for this instruction
AddedInstrns &AI = AddedInstrMap[MInst];
// We may need a scratch register to copy the spilled value to/from memory.
// This may itself have to insert code to free up a scratch register.
// Any such code should go before (after) the spill code for a load (store).
// The scratch reg is not marked as used because it is only used
// for the copy and not used across MInst.
int scratchRegType = -1;
int scratchReg = -1;
if (MRI.regTypeNeedsScratchReg(RegType, scratchRegType)) {
scratchReg = getUsableUniRegAtMI(scratchRegType, &LVSetBef,
MInst, MIBef, MIAft);
assert(scratchReg != MRI.getInvalidRegNum());
}
if (isUse) {
// for a USE, we have to load the value of LR from stack to a TmpReg
// and use the TmpReg as one operand of instruction
// actual loading instruction(s)
MRI.cpMem2RegMI(AdIMid, MRI.getFramePointer(), SpillOff, TmpRegU,
RegType, scratchReg);
// the actual load should be after the instructions to free up TmpRegU
MIBef.insert(MIBef.end(), AdIMid.begin(), AdIMid.end());
AdIMid.clear();
}
if (isDef) { // if this is a Def
// for a DEF, we have to store the value produced by this instruction
// on the stack position allocated for this LR
// actual storing instruction(s)
MRI.cpReg2MemMI(AdIMid, TmpRegU, MRI.getFramePointer(), SpillOff,
RegType, scratchReg);
MIAft.insert(MIAft.begin(), AdIMid.begin(), AdIMid.end());
} // if !DEF
// Finally, insert the entire spill code sequences before/after MInst
AI.InstrnsBefore.insert(AI.InstrnsBefore.end(), MIBef.begin(), MIBef.end());
AI.InstrnsAfter.insert(AI.InstrnsAfter.begin(), MIAft.begin(), MIAft.end());
if (DEBUG_RA) {
std::cerr << "\nFor Inst:\n " << *MInst;
std::cerr << "SPILLED LR# " << LR->getUserIGNode()->getIndex();
std::cerr << "; added Instructions:";
for_each(MIBef.begin(), MIBef.end(), std::mem_fun(&MachineInstr::dump));
for_each(MIAft.begin(), MIAft.end(), std::mem_fun(&MachineInstr::dump));
}
}
/// Insert caller saving/restoring instructions before/after a call machine
/// instruction (before or after any other instructions that were inserted for
/// the call).
///
void
PhyRegAlloc::insertCallerSavingCode(std::vector<MachineInstr*> &instrnsBefore,
std::vector<MachineInstr*> &instrnsAfter,
MachineInstr *CallMI,
const BasicBlock *BB) {
assert(TM.getInstrInfo().isCall(CallMI->getOpCode()));
// hash set to record which registers were saved/restored
hash_set<unsigned> PushedRegSet;
CallArgsDescriptor* argDesc = CallArgsDescriptor::get(CallMI);
// if the call is to a instrumentation function, do not insert save and
// restore instructions the instrumentation function takes care of save
// restore for volatile regs.
//
// FIXME: this should be made general, not specific to the reoptimizer!
const Function *Callee = argDesc->getCallInst()->getCalledFunction();
bool isLLVMFirstTrigger = Callee && Callee->getName() == "llvm_first_trigger";
// Now check if the call has a return value (using argDesc) and if so,
// find the LR of the TmpInstruction representing the return value register.
// (using the last or second-last *implicit operand* of the call MI).
// Insert it to to the PushedRegSet since we must not save that register
// and restore it after the call.
// We do this because, we look at the LV set *after* the instruction
// to determine, which LRs must be saved across calls. The return value
// of the call is live in this set - but we must not save/restore it.
if (const Value *origRetVal = argDesc->getReturnValue()) {
unsigned retValRefNum = (CallMI->getNumImplicitRefs() -
(argDesc->getIndirectFuncPtr()? 1 : 2));
const TmpInstruction* tmpRetVal =
cast<TmpInstruction>(CallMI->getImplicitRef(retValRefNum));
assert(tmpRetVal->getOperand(0) == origRetVal &&
tmpRetVal->getType() == origRetVal->getType() &&
"Wrong implicit ref?");
LiveRange *RetValLR = LRI->getLiveRangeForValue(tmpRetVal);
assert(RetValLR && "No LR for RetValue of call");
if (! RetValLR->isMarkedForSpill())
PushedRegSet.insert(MRI.getUnifiedRegNum(RetValLR->getRegClassID(),
RetValLR->getColor()));
}
const ValueSet &LVSetAft = LVI->getLiveVarSetAfterMInst(CallMI, BB);
ValueSet::const_iterator LIt = LVSetAft.begin();
// for each live var in live variable set after machine inst
for( ; LIt != LVSetAft.end(); ++LIt) {
// get the live range corresponding to live var
LiveRange *const LR = LRI->getLiveRangeForValue(*LIt);
// LR can be null if it is a const since a const
// doesn't have a dominating def - see Assumptions above
if (LR) {
if (! LR->isMarkedForSpill()) {
assert(LR->hasColor() && "LR is neither spilled nor colored?");
unsigned RCID = LR->getRegClassID();
unsigned Color = LR->getColor();
if (MRI.isRegVolatile(RCID, Color) ) {
// if this is a call to the first-level reoptimizer
// instrumentation entry point, and the register is not
// modified by call, don't save and restore it.
if (isLLVMFirstTrigger && !MRI.modifiedByCall(RCID, Color))
continue;
// if the value is in both LV sets (i.e., live before and after
// the call machine instruction)
unsigned Reg = MRI.getUnifiedRegNum(RCID, Color);
// if we haven't already pushed this register...
if( PushedRegSet.find(Reg) == PushedRegSet.end() ) {
unsigned RegType = MRI.getRegTypeForLR(LR);
// Now get two instructions - to push on stack and pop from stack
// and add them to InstrnsBefore and InstrnsAfter of the
// call instruction
int StackOff =
MF->getInfo()->pushTempValue(MRI.getSpilledRegSize(RegType));
//---- Insert code for pushing the reg on stack ----------
std::vector<MachineInstr*> AdIBef, AdIAft;
// We may need a scratch register to copy the saved value
// to/from memory. This may itself have to insert code to
// free up a scratch register. Any such code should go before
// the save code. The scratch register, if any, is by default
// temporary and not "used" by the instruction unless the
// copy code itself decides to keep the value in the scratch reg.
int scratchRegType = -1;
int scratchReg = -1;
if (MRI.regTypeNeedsScratchReg(RegType, scratchRegType))
{ // Find a register not live in the LVSet before CallMI
const ValueSet &LVSetBef =
LVI->getLiveVarSetBeforeMInst(CallMI, BB);
scratchReg = getUsableUniRegAtMI(scratchRegType, &LVSetBef,
CallMI, AdIBef, AdIAft);
assert(scratchReg != MRI.getInvalidRegNum());
}
if (AdIBef.size() > 0)
instrnsBefore.insert(instrnsBefore.end(),
AdIBef.begin(), AdIBef.end());
MRI.cpReg2MemMI(instrnsBefore, Reg, MRI.getFramePointer(),
StackOff, RegType, scratchReg);
if (AdIAft.size() > 0)
instrnsBefore.insert(instrnsBefore.end(),
AdIAft.begin(), AdIAft.end());
//---- Insert code for popping the reg from the stack ----------
AdIBef.clear();
AdIAft.clear();
// We may need a scratch register to copy the saved value
// from memory. This may itself have to insert code to
// free up a scratch register. Any such code should go
// after the save code. As above, scratch is not marked "used".
scratchRegType = -1;
scratchReg = -1;
if (MRI.regTypeNeedsScratchReg(RegType, scratchRegType))
{ // Find a register not live in the LVSet after CallMI
scratchReg = getUsableUniRegAtMI(scratchRegType, &LVSetAft,
CallMI, AdIBef, AdIAft);
assert(scratchReg != MRI.getInvalidRegNum());
}
if (AdIBef.size() > 0)
instrnsAfter.insert(instrnsAfter.end(),
AdIBef.begin(), AdIBef.end());
MRI.cpMem2RegMI(instrnsAfter, MRI.getFramePointer(), StackOff,
Reg, RegType, scratchReg);
if (AdIAft.size() > 0)
instrnsAfter.insert(instrnsAfter.end(),
AdIAft.begin(), AdIAft.end());
PushedRegSet.insert(Reg);
if(DEBUG_RA) {
std::cerr << "\nFor call inst:" << *CallMI;
std::cerr << " -inserted caller saving instrs: Before:\n\t ";
for_each(instrnsBefore.begin(), instrnsBefore.end(),
std::mem_fun(&MachineInstr::dump));
std::cerr << " -and After:\n\t ";
for_each(instrnsAfter.begin(), instrnsAfter.end(),
std::mem_fun(&MachineInstr::dump));
}
} // if not already pushed
} // if LR has a volatile color
} // if LR has color
} // if there is a LR for Var
} // for each value in the LV set after instruction
}
/// Returns the unified register number of a temporary register to be used
/// BEFORE MInst. If no register is available, it will pick one and modify
/// MIBef and MIAft to contain instructions used to free up this returned
/// register.
///
int PhyRegAlloc::getUsableUniRegAtMI(const int RegType,
const ValueSet *LVSetBef,
MachineInstr *MInst,
std::vector<MachineInstr*>& MIBef,
std::vector<MachineInstr*>& MIAft) {
RegClass* RC = getRegClassByID(MRI.getRegClassIDOfRegType(RegType));
int RegU = getUnusedUniRegAtMI(RC, RegType, MInst, LVSetBef);
if (RegU == -1) {
// we couldn't find an unused register. Generate code to free up a reg by
// saving it on stack and restoring after the instruction
int TmpOff = MF->getInfo()->pushTempValue(MRI.getSpilledRegSize(RegType));
RegU = getUniRegNotUsedByThisInst(RC, RegType, MInst);
// Check if we need a scratch register to copy this register to memory.
int scratchRegType = -1;
if (MRI.regTypeNeedsScratchReg(RegType, scratchRegType)) {
int scratchReg = getUsableUniRegAtMI(scratchRegType, LVSetBef,
MInst, MIBef, MIAft);
assert(scratchReg != MRI.getInvalidRegNum());
// We may as well hold the value in the scratch register instead
// of copying it to memory and back. But we have to mark the
// register as used by this instruction, so it does not get used
// as a scratch reg. by another operand or anyone else.
ScratchRegsUsed.insert(std::make_pair(MInst, scratchReg));
MRI.cpReg2RegMI(MIBef, RegU, scratchReg, RegType);
MRI.cpReg2RegMI(MIAft, scratchReg, RegU, RegType);
} else { // the register can be copied directly to/from memory so do it.
MRI.cpReg2MemMI(MIBef, RegU, MRI.getFramePointer(), TmpOff, RegType);
MRI.cpMem2RegMI(MIAft, MRI.getFramePointer(), TmpOff, RegU, RegType);
}
}
return RegU;
}
/// Returns the register-class register number of a new unused register that
/// can be used to accommodate a temporary value. May be called repeatedly
/// for a single MachineInstr. On each call, it finds a register which is not
/// live at that instruction and which is not used by any spilled operands of
/// that instruction.
///
int PhyRegAlloc::getUnusedUniRegAtMI(RegClass *RC, const int RegType,
const MachineInstr *MInst,
const ValueSet* LVSetBef) {
RC->clearColorsUsed(); // Reset array
if (LVSetBef == NULL) {
LVSetBef = &LVI->getLiveVarSetBeforeMInst(MInst);
assert(LVSetBef != NULL && "Unable to get live-var set before MInst?");
}
ValueSet::const_iterator LIt = LVSetBef->begin();
// for each live var in live variable set after machine inst
for ( ; LIt != LVSetBef->end(); ++LIt) {
// Get the live range corresponding to live var, and its RegClass
LiveRange *const LRofLV = LRI->getLiveRangeForValue(*LIt );
// LR can be null if it is a const since a const
// doesn't have a dominating def - see Assumptions above
if (LRofLV && LRofLV->getRegClass() == RC && LRofLV->hasColor())
RC->markColorsUsed(LRofLV->getColor(),
MRI.getRegTypeForLR(LRofLV), RegType);
}
// It is possible that one operand of this MInst was already spilled
// and it received some register temporarily. If that's the case,
// it is recorded in machine operand. We must skip such registers.
setRelRegsUsedByThisInst(RC, RegType, MInst);
int unusedReg = RC->getUnusedColor(RegType); // find first unused color
if (unusedReg >= 0)
return MRI.getUnifiedRegNum(RC->getID(), unusedReg);
return -1;
}
/// Return the unified register number of a register in class RC which is not
/// used by any operands of MInst.
///
int PhyRegAlloc::getUniRegNotUsedByThisInst(RegClass *RC,
const int RegType,
const MachineInstr *MInst) {
RC->clearColorsUsed();
setRelRegsUsedByThisInst(RC, RegType, MInst);
// find the first unused color
int unusedReg = RC->getUnusedColor(RegType);
assert(unusedReg >= 0 &&
"FATAL: No free register could be found in reg class!!");
return MRI.getUnifiedRegNum(RC->getID(), unusedReg);
}
/// Modify the IsColorUsedArr of register class RC, by setting the bits
/// corresponding to register RegNo. This is a helper method of
/// setRelRegsUsedByThisInst().
///
static void markRegisterUsed(int RegNo, RegClass *RC, int RegType,
const TargetRegInfo &TRI) {
unsigned classId = 0;
int classRegNum = TRI.getClassRegNum(RegNo, classId);
if (RC->getID() == classId)
RC->markColorsUsed(classRegNum, RegType, RegType);
}
void PhyRegAlloc::setRelRegsUsedByThisInst(RegClass *RC, int RegType,
const MachineInstr *MI) {
assert(OperandsColoredMap[MI] == true &&
"Illegal to call setRelRegsUsedByThisInst() until colored operands "
"are marked for an instruction.");
// Add the registers already marked as used by the instruction. Both
// explicit and implicit operands are set.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
if (MI->getOperand(i).hasAllocatedReg())
markRegisterUsed(MI->getOperand(i).getAllocatedRegNum(), RC, RegType,MRI);
for (unsigned i = 0, e = MI->getNumImplicitRefs(); i != e; ++i)
if (MI->getImplicitOp(i).hasAllocatedReg())
markRegisterUsed(MI->getImplicitOp(i).getAllocatedRegNum(), RC,
RegType,MRI);
// Add all of the scratch registers that are used to save values across the
// instruction (e.g., for saving state register values).
std::pair<ScratchRegsUsedTy::iterator, ScratchRegsUsedTy::iterator>
IR = ScratchRegsUsed.equal_range(MI);
for (ScratchRegsUsedTy::iterator I = IR.first; I != IR.second; ++I)
markRegisterUsed(I->second, RC, RegType, MRI);
// If there are implicit references, mark their allocated regs as well
for (unsigned z=0; z < MI->getNumImplicitRefs(); z++)
if (const LiveRange*
LRofImpRef = LRI->getLiveRangeForValue(MI->getImplicitRef(z)))
if (LRofImpRef->hasColor())
// this implicit reference is in a LR that received a color
RC->markColorsUsed(LRofImpRef->getColor(),
MRI.getRegTypeForLR(LRofImpRef), RegType);
}
/// If there are delay slots for an instruction, the instructions added after
/// it must really go after the delayed instruction(s). So, we Move the
/// InstrAfter of that instruction to the corresponding delayed instruction
/// using the following method.
///
void PhyRegAlloc::move2DelayedInstr(const MachineInstr *OrigMI,
const MachineInstr *DelayedMI)
{
// "added after" instructions of the original instr
std::vector<MachineInstr *> &OrigAft = AddedInstrMap[OrigMI].InstrnsAfter;
if (DEBUG_RA && OrigAft.size() > 0) {
std::cerr << "\nRegAlloc: Moved InstrnsAfter for: " << *OrigMI;
std::cerr << " to last delay slot instrn: " << *DelayedMI;
}
// "added after" instructions of the delayed instr
std::vector<MachineInstr *> &DelayedAft=AddedInstrMap[DelayedMI].InstrnsAfter;
// go thru all the "added after instructions" of the original instruction
// and append them to the "added after instructions" of the delayed
// instructions
DelayedAft.insert(DelayedAft.end(), OrigAft.begin(), OrigAft.end());
// empty the "added after instructions" of the original instruction
OrigAft.clear();
}
void PhyRegAlloc::colorIncomingArgs()
{
MRI.colorMethodArgs(Fn, *LRI, AddedInstrAtEntry.InstrnsBefore,
AddedInstrAtEntry.InstrnsAfter);
}
/// Determine whether the suggested color of each live range is really usable,
/// and then call its setSuggestedColorUsable() method to record the answer. A
/// suggested color is NOT usable when the suggested color is volatile AND
/// when there are call interferences.
///
void PhyRegAlloc::markUnusableSugColors()
{
LiveRangeMapType::const_iterator HMI = (LRI->getLiveRangeMap())->begin();
LiveRangeMapType::const_iterator HMIEnd = (LRI->getLiveRangeMap())->end();
for (; HMI != HMIEnd ; ++HMI ) {
if (HMI->first) {
LiveRange *L = HMI->second; // get the LiveRange
if (L && L->hasSuggestedColor ())
L->setSuggestedColorUsable
(!(MRI.isRegVolatile (L->getRegClassID (), L->getSuggestedColor ())
&& L->isCallInterference ()));
}
} // for all LR's in hash map
}
/// For each live range that is spilled, allocates a new spill position on the
/// stack, and set the stack offsets of the live range that will be spilled to
/// that position. This must be called just after coloring the LRs.
///
void PhyRegAlloc::allocateStackSpace4SpilledLRs() {
if (DEBUG_RA) std::cerr << "\nSetting LR stack offsets for spills...\n";
LiveRangeMapType::const_iterator HMI = LRI->getLiveRangeMap()->begin();
LiveRangeMapType::const_iterator HMIEnd = LRI->getLiveRangeMap()->end();
for ( ; HMI != HMIEnd ; ++HMI) {
if (HMI->first && HMI->second) {
LiveRange *L = HMI->second; // get the LiveRange
if (L->isMarkedForSpill()) { // NOTE: allocating size of long Type **
int stackOffset = MF->getInfo()->allocateSpilledValue(Type::LongTy);
L->setSpillOffFromFP(stackOffset);
if (DEBUG_RA)
std::cerr << " LR# " << L->getUserIGNode()->getIndex()
<< ": stack-offset = " << stackOffset << "\n";
}
}
} // for all LR's in hash map
}
void PhyRegAlloc::saveStateForValue (std::vector<AllocInfo> &state,
const Value *V, unsigned Insn, int Opnd) {
LiveRangeMapType::const_iterator HMI = LRI->getLiveRangeMap ()->find (V);
LiveRangeMapType::const_iterator HMIEnd = LRI->getLiveRangeMap ()->end ();
AllocInfo::AllocStateTy AllocState = AllocInfo::NotAllocated;
int Placement = -1;
if ((HMI != HMIEnd) && HMI->second) {
LiveRange *L = HMI->second;
assert ((L->hasColor () || L->isMarkedForSpill ())
&& "Live range exists but not colored or spilled");
if (L->hasColor ()) {
AllocState = AllocInfo::Allocated;
Placement = MRI.getUnifiedRegNum (L->getRegClassID (),
L->getColor ());
} else if (L->isMarkedForSpill ()) {
AllocState = AllocInfo::Spilled;
assert (L->hasSpillOffset ()
&& "Live range marked for spill but has no spill offset");
Placement = L->getSpillOffFromFP ();
}
}
state.push_back (AllocInfo (Insn, Opnd, AllocState, Placement));
}
/// Save the global register allocation decisions made by the register
/// allocator so that they can be accessed later (sort of like "poor man's
/// debug info").
///
void PhyRegAlloc::saveState () {
std::vector<AllocInfo> &state = FnAllocState[Fn];
unsigned Insn = 0;
for (const_inst_iterator II=inst_begin (Fn), IE=inst_end (Fn); II!=IE; ++II){
saveStateForValue (state, (*II), Insn, -1);
for (unsigned i = 0; i < (*II)->getNumOperands (); ++i) {
const Value *V = (*II)->getOperand (i);
// Don't worry about it unless it's something whose reg. we'll need.
if (!isa<Argument> (V) && !isa<Instruction> (V))
continue;
saveStateForValue (state, V, Insn, i);
}
++Insn;
}
}
/// Check the saved state filled in by saveState(), and abort if it looks
/// wrong. Only used when debugging. FIXME: Currently it just prints out
/// the state, which isn't quite as useful.
///
void PhyRegAlloc::verifySavedState () {
std::vector<AllocInfo> &state = FnAllocState[Fn];
unsigned Insn = 0;
for (const_inst_iterator II=inst_begin (Fn), IE=inst_end (Fn); II!=IE; ++II) {
const Instruction *I = *II;
MachineCodeForInstruction &Instrs = MachineCodeForInstruction::get (I);
std::cerr << "Instruction:\n" << " " << *I << "\n"
<< "MachineCodeForInstruction:\n";
for (unsigned i = 0, n = Instrs.size (); i != n; ++i)
std::cerr << " " << *Instrs[i] << "\n";
std::cerr << "FnAllocState:\n";
for (unsigned i = 0; i < state.size (); ++i) {
AllocInfo &S = state[i];
if (Insn == S.Instruction) {
std::cerr << " (Instruction " << S.Instruction
<< ", Operand " << S.Operand
<< ", AllocState " << S.allocStateToString ()
<< ", Placement " << S.Placement << ")\n";
}
}
std::cerr << "----------\n";
++Insn;
}
}
/// Finish the job of saveState(), by collapsing FnAllocState into an LLVM
/// Constant and stuffing it inside the Module. (NOTE: Soon, there will be
/// other, better ways of storing the saved state; this one is cumbersome and
/// does not work well with the JIT.)
///
bool PhyRegAlloc::doFinalization (Module &M) {
if (!SaveRegAllocState)
return false; // Nothing to do here, unless we're saving state.
// If saving state into the module, just copy new elements to the
// correct global.
if (!SaveStateToModule) {
ExportedFnAllocState = FnAllocState;
// FIXME: should ONLY copy new elements in FnAllocState
return false;
}
// Convert FnAllocState to a single Constant array and add it
// to the Module.
ArrayType *AT = ArrayType::get (AllocInfo::getConstantType (), 0);
std::vector<const Type *> TV;
TV.push_back (Type::UIntTy);
TV.push_back (AT);
PointerType *PT = PointerType::get (StructType::get (TV));
std::vector<Constant *> allstate;
for (Module::iterator I = M.begin (), E = M.end (); I != E; ++I) {
Function *F = I;
if (F->isExternal ()) continue;
if (FnAllocState.find (F) == FnAllocState.end ()) {
allstate.push_back (ConstantPointerNull::get (PT));
} else {
std::vector<AllocInfo> &state = FnAllocState[F];
// Convert state into an LLVM ConstantArray, and put it in a
// ConstantStruct (named S) along with its size.
std::vector<Constant *> stateConstants;
for (unsigned i = 0, s = state.size (); i != s; ++i)
stateConstants.push_back (state[i].toConstant ());
unsigned Size = stateConstants.size ();
ArrayType *AT = ArrayType::get (AllocInfo::getConstantType (), Size);
std::vector<const Type *> TV;
TV.push_back (Type::UIntTy);
TV.push_back (AT);
StructType *ST = StructType::get (TV);
std::vector<Constant *> CV;
CV.push_back (ConstantUInt::get (Type::UIntTy, Size));
CV.push_back (ConstantArray::get (AT, stateConstants));
Constant *S = ConstantStruct::get (ST, CV);
GlobalVariable *GV =
new GlobalVariable (ST, true,
GlobalValue::InternalLinkage, S,
F->getName () + ".regAllocState", &M);
// Have: { uint, [Size x { uint, int, uint, int }] } *
// Cast it to: { uint, [0 x { uint, int, uint, int }] } *
Constant *CE = ConstantExpr::getCast (ConstantPointerRef::get (GV), PT);
allstate.push_back (CE);
}
}
unsigned Size = allstate.size ();
// Final structure type is:
// { uint, [Size x { uint, [0 x { uint, int, uint, int }] } *] }
std::vector<const Type *> TV2;
TV2.push_back (Type::UIntTy);
ArrayType *AT2 = ArrayType::get (PT, Size);
TV2.push_back (AT2);
StructType *ST2 = StructType::get (TV2);
std::vector<Constant *> CV2;
CV2.push_back (ConstantUInt::get (Type::UIntTy, Size));
CV2.push_back (ConstantArray::get (AT2, allstate));
new GlobalVariable (ST2, true, GlobalValue::ExternalLinkage,
ConstantStruct::get (ST2, CV2), "_llvm_regAllocState",
&M);
return false; // No error.
}
/// Allocate registers for the machine code previously generated for F using
/// the graph-coloring algorithm.
///
bool PhyRegAlloc::runOnFunction (Function &F) {
if (DEBUG_RA)
std::cerr << "\n********* Function "<< F.getName () << " ***********\n";
Fn = &F;
MF = &MachineFunction::get (Fn);
LVI = &getAnalysis<FunctionLiveVarInfo> ();
LRI = new LiveRangeInfo (Fn, TM, RegClassList);
LoopDepthCalc = &getAnalysis<LoopInfo> ();
// Create each RegClass for the target machine and add it to the
// RegClassList. This must be done before calling constructLiveRanges().
for (unsigned rc = 0; rc != NumOfRegClasses; ++rc)
RegClassList.push_back (new RegClass (Fn, &TM.getRegInfo (),
MRI.getMachineRegClass (rc)));
LRI->constructLiveRanges(); // create LR info
if (DEBUG_RA >= RA_DEBUG_LiveRanges)
LRI->printLiveRanges();
createIGNodeListsAndIGs(); // create IGNode list and IGs
buildInterferenceGraphs(); // build IGs in all reg classes
if (DEBUG_RA >= RA_DEBUG_LiveRanges) {
// print all LRs in all reg classes
for ( unsigned rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[rc]->printIGNodeList();
// print IGs in all register classes
for ( unsigned rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[rc]->printIG();
}
LRI->coalesceLRs(); // coalesce all live ranges
if (DEBUG_RA >= RA_DEBUG_LiveRanges) {
// print all LRs in all reg classes
for (unsigned rc=0; rc < NumOfRegClasses; rc++)
RegClassList[rc]->printIGNodeList();
// print IGs in all register classes
for (unsigned rc=0; rc < NumOfRegClasses; rc++)
RegClassList[rc]->printIG();
}
// mark un-usable suggested color before graph coloring algorithm.
// When this is done, the graph coloring algo will not reserve
// suggested color unnecessarily - they can be used by another LR
markUnusableSugColors();
// color all register classes using the graph coloring algo
for (unsigned rc=0; rc < NumOfRegClasses ; rc++)
RegClassList[rc]->colorAllRegs();
// After graph coloring, if some LRs did not receive a color (i.e, spilled)
// a position for such spilled LRs
allocateStackSpace4SpilledLRs();
// Reset the temp. area on the stack before use by the first instruction.
// This will also happen after updating each instruction.
MF->getInfo()->popAllTempValues();
// color incoming args - if the correct color was not received
// insert code to copy to the correct register
colorIncomingArgs();
// Save register allocation state for this function in a Constant.
if (SaveRegAllocState)
saveState();
if (DEBUG_RA) { // Check our work.
verifySavedState ();
}
// Now update the machine code with register names and add any additional
// code inserted by the register allocator to the instruction stream.
updateMachineCode();
if (DEBUG_RA) {
std::cerr << "\n**** Machine Code After Register Allocation:\n\n";
MF->dump();
}
// Tear down temporary data structures
for (unsigned rc = 0; rc < NumOfRegClasses; ++rc)
delete RegClassList[rc];
RegClassList.clear ();
AddedInstrMap.clear ();
OperandsColoredMap.clear ();
ScratchRegsUsed.clear ();
AddedInstrAtEntry.clear ();
delete LRI;
if (DEBUG_RA) std::cerr << "\nRegister allocation complete!\n";
return false; // Function was not modified
}
} // End llvm namespace
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