mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-19 19:29:31 +00:00
handled like normal operands, not like other call arguments. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3967 91177308-0d34-0410-b5e6-96231b3b80d8
1142 lines
41 KiB
C++
1142 lines
41 KiB
C++
//===-- PhyRegAlloc.cpp ---------------------------------------------------===//
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//
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// Register allocation for LLVM.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/RegisterAllocation.h"
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#include "llvm/CodeGen/RegAllocCommon.h"
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#include "llvm/CodeGen/PhyRegAlloc.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineInstrAnnot.h"
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#include "llvm/CodeGen/MachineCodeForBasicBlock.h"
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#include "llvm/CodeGen/MachineCodeForMethod.h"
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#include "llvm/Analysis/LiveVar/FunctionLiveVarInfo.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/MachineFrameInfo.h"
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#include "llvm/Function.h"
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#include "llvm/Type.h"
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#include "llvm/iOther.h"
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#include "Support/STLExtras.h"
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#include "Support/CommandLine.h"
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#include <math.h>
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using std::cerr;
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using std::vector;
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RegAllocDebugLevel_t DEBUG_RA;
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static cl::opt<RegAllocDebugLevel_t, true>
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DRA_opt("dregalloc", cl::Hidden, cl::location(DEBUG_RA),
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cl::desc("enable register allocation debugging information"),
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cl::values(
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clEnumValN(RA_DEBUG_None , "n", "disable debug output"),
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clEnumValN(RA_DEBUG_Results, "y", "debug output for allocation results"),
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clEnumValN(RA_DEBUG_Coloring, "c", "debug output for graph coloring step"),
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clEnumValN(RA_DEBUG_Interference,"ig","debug output for interference graphs"),
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clEnumValN(RA_DEBUG_LiveRanges , "lr","debug output for live ranges"),
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clEnumValN(RA_DEBUG_Verbose, "v", "extra debug output"),
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0));
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//----------------------------------------------------------------------------
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// RegisterAllocation pass front end...
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//----------------------------------------------------------------------------
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namespace {
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class RegisterAllocator : public FunctionPass {
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TargetMachine &Target;
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public:
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inline RegisterAllocator(TargetMachine &T) : Target(T) {}
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const char *getPassName() const { return "Register Allocation"; }
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bool runOnFunction(Function &F) {
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if (DEBUG_RA)
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cerr << "\n********* Function "<< F.getName() << " ***********\n";
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PhyRegAlloc PRA(&F, Target, &getAnalysis<FunctionLiveVarInfo>(),
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&getAnalysis<LoopInfo>());
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PRA.allocateRegisters();
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if (DEBUG_RA) cerr << "\nRegister allocation complete!\n";
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return false;
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}
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<LoopInfo>();
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AU.addRequired<FunctionLiveVarInfo>();
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}
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};
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}
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Pass *getRegisterAllocator(TargetMachine &T) {
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return new RegisterAllocator(T);
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}
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//----------------------------------------------------------------------------
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// Constructor: Init local composite objects and create register classes.
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//----------------------------------------------------------------------------
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PhyRegAlloc::PhyRegAlloc(Function *F, const TargetMachine& tm,
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FunctionLiveVarInfo *Lvi, LoopInfo *LDC)
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: TM(tm), Meth(F),
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mcInfo(MachineCodeForMethod::get(F)),
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LVI(Lvi), LRI(F, tm, RegClassList),
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MRI(tm.getRegInfo()),
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NumOfRegClasses(MRI.getNumOfRegClasses()),
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LoopDepthCalc(LDC) {
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// create each RegisterClass and put in RegClassList
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//
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for (unsigned rc=0; rc < NumOfRegClasses; rc++)
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RegClassList.push_back(new RegClass(F, MRI.getMachineRegClass(rc),
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&ResColList));
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}
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//----------------------------------------------------------------------------
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// Destructor: Deletes register classes
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//----------------------------------------------------------------------------
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PhyRegAlloc::~PhyRegAlloc() {
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for ( unsigned rc=0; rc < NumOfRegClasses; rc++)
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delete RegClassList[rc];
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AddedInstrMap.clear();
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}
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//----------------------------------------------------------------------------
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// This method initally creates interference graphs (one in each reg class)
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// and IGNodeList (one in each IG). The actual nodes will be pushed later.
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//----------------------------------------------------------------------------
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void PhyRegAlloc::createIGNodeListsAndIGs() {
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if (DEBUG_RA >= RA_DEBUG_LiveRanges) cerr << "Creating LR lists ...\n";
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// hash map iterator
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LiveRangeMapType::const_iterator HMI = LRI.getLiveRangeMap()->begin();
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// hash map end
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LiveRangeMapType::const_iterator HMIEnd = LRI.getLiveRangeMap()->end();
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for (; HMI != HMIEnd ; ++HMI ) {
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if (HMI->first) {
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LiveRange *L = HMI->second; // get the LiveRange
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if (!L) {
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if (DEBUG_RA)
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cerr << "\n**** ?!?WARNING: NULL LIVE RANGE FOUND FOR: "
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<< RAV(HMI->first) << "****\n";
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continue;
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}
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// if the Value * is not null, and LR is not yet written to the IGNodeList
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if (!(L->getUserIGNode()) ) {
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RegClass *const RC = // RegClass of first value in the LR
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RegClassList[ L->getRegClass()->getID() ];
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RC->addLRToIG(L); // add this LR to an IG
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}
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}
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}
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// init RegClassList
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for ( unsigned rc=0; rc < NumOfRegClasses ; rc++)
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RegClassList[rc]->createInterferenceGraph();
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if (DEBUG_RA >= RA_DEBUG_LiveRanges) cerr << "LRLists Created!\n";
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}
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//----------------------------------------------------------------------------
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// This method will add all interferences at for a given instruction.
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// Interence occurs only if the LR of Def (Inst or Arg) is of the same reg
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// class as that of live var. The live var passed to this function is the
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// LVset AFTER the instruction
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//----------------------------------------------------------------------------
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void PhyRegAlloc::addInterference(const Value *Def,
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const ValueSet *LVSet,
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bool isCallInst) {
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ValueSet::const_iterator LIt = LVSet->begin();
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// get the live range of instruction
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//
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const LiveRange *const LROfDef = LRI.getLiveRangeForValue( Def );
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IGNode *const IGNodeOfDef = LROfDef->getUserIGNode();
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assert( IGNodeOfDef );
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RegClass *const RCOfDef = LROfDef->getRegClass();
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// for each live var in live variable set
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//
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for ( ; LIt != LVSet->end(); ++LIt) {
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if (DEBUG_RA >= RA_DEBUG_Verbose)
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cerr << "< Def=" << RAV(Def) << ", Lvar=" << RAV(*LIt) << "> ";
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// get the live range corresponding to live var
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//
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LiveRange *LROfVar = LRI.getLiveRangeForValue(*LIt);
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// LROfVar can be null if it is a const since a const
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// doesn't have a dominating def - see Assumptions above
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//
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if (LROfVar)
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if (LROfDef != LROfVar) // do not set interf for same LR
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if (RCOfDef == LROfVar->getRegClass()) // 2 reg classes are the same
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RCOfDef->setInterference( LROfDef, LROfVar);
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}
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}
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//----------------------------------------------------------------------------
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// For a call instruction, this method sets the CallInterference flag in
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// the LR of each variable live int the Live Variable Set live after the
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// call instruction (except the return value of the call instruction - since
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// the return value does not interfere with that call itself).
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//----------------------------------------------------------------------------
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void PhyRegAlloc::setCallInterferences(const MachineInstr *MInst,
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const ValueSet *LVSetAft) {
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if (DEBUG_RA >= RA_DEBUG_Interference)
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cerr << "\n For call inst: " << *MInst;
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ValueSet::const_iterator LIt = LVSetAft->begin();
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// for each live var in live variable set after machine inst
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//
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for ( ; LIt != LVSetAft->end(); ++LIt) {
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// get the live range corresponding to live var
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//
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LiveRange *const LR = LRI.getLiveRangeForValue(*LIt );
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// LR can be null if it is a const since a const
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// doesn't have a dominating def - see Assumptions above
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//
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if (LR ) {
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if (DEBUG_RA >= RA_DEBUG_Interference) {
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cerr << "\n\tLR after Call: ";
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printSet(*LR);
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}
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LR->setCallInterference();
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if (DEBUG_RA >= RA_DEBUG_Interference) {
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cerr << "\n ++After adding call interference for LR: " ;
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printSet(*LR);
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}
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}
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}
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// Now find the LR of the return value of the call
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// We do this because, we look at the LV set *after* the instruction
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// to determine, which LRs must be saved across calls. The return value
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// of the call is live in this set - but it does not interfere with call
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// (i.e., we can allocate a volatile register to the return value)
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//
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CallArgsDescriptor* argDesc = CallArgsDescriptor::get(MInst);
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if (const Value *RetVal = argDesc->getReturnValue()) {
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LiveRange *RetValLR = LRI.getLiveRangeForValue( RetVal );
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assert( RetValLR && "No LR for RetValue of call");
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RetValLR->clearCallInterference();
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}
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// If the CALL is an indirect call, find the LR of the function pointer.
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// That has a call interference because it conflicts with outgoing args.
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if (const Value *AddrVal = argDesc->getIndirectFuncPtr()) {
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LiveRange *AddrValLR = LRI.getLiveRangeForValue( AddrVal );
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assert( AddrValLR && "No LR for indirect addr val of call");
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AddrValLR->setCallInterference();
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}
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}
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//----------------------------------------------------------------------------
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// This method will walk thru code and create interferences in the IG of
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// each RegClass. Also, this method calculates the spill cost of each
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// Live Range (it is done in this method to save another pass over the code).
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//----------------------------------------------------------------------------
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void PhyRegAlloc::buildInterferenceGraphs()
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{
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if (DEBUG_RA >= RA_DEBUG_Interference)
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cerr << "Creating interference graphs ...\n";
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unsigned BBLoopDepthCost;
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for (Function::const_iterator BBI = Meth->begin(), BBE = Meth->end();
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BBI != BBE; ++BBI) {
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// find the 10^(loop_depth) of this BB
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//
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BBLoopDepthCost = (unsigned)pow(10.0, LoopDepthCalc->getLoopDepth(BBI));
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// get the iterator for machine instructions
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//
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const MachineCodeForBasicBlock& MIVec = MachineCodeForBasicBlock::get(BBI);
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MachineCodeForBasicBlock::const_iterator MII = MIVec.begin();
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// iterate over all the machine instructions in BB
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//
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for ( ; MII != MIVec.end(); ++MII) {
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const MachineInstr *MInst = *MII;
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// get the LV set after the instruction
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//
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const ValueSet &LVSetAI = LVI->getLiveVarSetAfterMInst(MInst, BBI);
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const bool isCallInst = TM.getInstrInfo().isCall(MInst->getOpCode());
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if (isCallInst ) {
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// set the isCallInterference flag of each live range wich extends
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// accross this call instruction. This information is used by graph
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// coloring algo to avoid allocating volatile colors to live ranges
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// that span across calls (since they have to be saved/restored)
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//
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setCallInterferences(MInst, &LVSetAI);
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}
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// iterate over all MI operands to find defs
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//
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for (MachineInstr::const_val_op_iterator OpI = MInst->begin(),
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OpE = MInst->end(); OpI != OpE; ++OpI) {
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if (OpI.isDef()) // create a new LR iff this operand is a def
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addInterference(*OpI, &LVSetAI, isCallInst);
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// Calculate the spill cost of each live range
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//
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LiveRange *LR = LRI.getLiveRangeForValue(*OpI);
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if (LR) LR->addSpillCost(BBLoopDepthCost);
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}
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// if there are multiple defs in this instruction e.g. in SETX
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//
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if (TM.getInstrInfo().isPseudoInstr(MInst->getOpCode()))
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addInterf4PseudoInstr(MInst);
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// Also add interference for any implicit definitions in a machine
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// instr (currently, only calls have this).
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//
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unsigned NumOfImpRefs = MInst->getNumImplicitRefs();
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if ( NumOfImpRefs > 0 ) {
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for (unsigned z=0; z < NumOfImpRefs; z++)
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if (MInst->implicitRefIsDefined(z) )
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addInterference( MInst->getImplicitRef(z), &LVSetAI, isCallInst );
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}
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} // for all machine instructions in BB
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} // for all BBs in function
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// add interferences for function arguments. Since there are no explict
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// defs in the function for args, we have to add them manually
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//
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addInterferencesForArgs();
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if (DEBUG_RA >= RA_DEBUG_Interference)
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cerr << "Interference graphs calculated!\n";
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}
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//--------------------------------------------------------------------------
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// Pseudo instructions will be exapnded to multiple instructions by the
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// assembler. Consequently, all the opernds must get distinct registers.
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// Therefore, we mark all operands of a pseudo instruction as they interfere
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// with one another.
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//--------------------------------------------------------------------------
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void PhyRegAlloc::addInterf4PseudoInstr(const MachineInstr *MInst) {
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bool setInterf = false;
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// iterate over MI operands to find defs
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//
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for (MachineInstr::const_val_op_iterator It1 = MInst->begin(),
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ItE = MInst->end(); It1 != ItE; ++It1) {
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const LiveRange *LROfOp1 = LRI.getLiveRangeForValue(*It1);
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assert((LROfOp1 || !It1.isDef()) && "No LR for Def in PSEUDO insruction");
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MachineInstr::const_val_op_iterator It2 = It1;
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for (++It2; It2 != ItE; ++It2) {
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const LiveRange *LROfOp2 = LRI.getLiveRangeForValue(*It2);
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if (LROfOp2) {
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RegClass *RCOfOp1 = LROfOp1->getRegClass();
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RegClass *RCOfOp2 = LROfOp2->getRegClass();
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if (RCOfOp1 == RCOfOp2 ){
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RCOfOp1->setInterference( LROfOp1, LROfOp2 );
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setInterf = true;
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}
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} // if Op2 has a LR
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} // for all other defs in machine instr
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} // for all operands in an instruction
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if (!setInterf && MInst->getNumOperands() > 2) {
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cerr << "\nInterf not set for any operand in pseudo instr:\n";
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cerr << *MInst;
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assert(0 && "Interf not set for pseudo instr with > 2 operands" );
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}
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}
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//----------------------------------------------------------------------------
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// This method will add interferences for incoming arguments to a function.
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//----------------------------------------------------------------------------
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void PhyRegAlloc::addInterferencesForArgs() {
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// get the InSet of root BB
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const ValueSet &InSet = LVI->getInSetOfBB(&Meth->front());
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for (Function::const_aiterator AI=Meth->abegin(); AI != Meth->aend(); ++AI) {
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// add interferences between args and LVars at start
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addInterference(AI, &InSet, false);
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if (DEBUG_RA >= RA_DEBUG_Interference)
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cerr << " - %% adding interference for argument " << RAV(AI) << "\n";
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}
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}
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//----------------------------------------------------------------------------
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// This method is called after register allocation is complete to set the
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// allocated reisters in the machine code. This code will add register numbers
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// to MachineOperands that contain a Value. Also it calls target specific
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// methods to produce caller saving instructions. At the end, it adds all
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// additional instructions produced by the register allocator to the
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// instruction stream.
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//----------------------------------------------------------------------------
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//-----------------------------
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// Utility functions used below
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//-----------------------------
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inline void
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PrependInstructions(vector<MachineInstr *> &IBef,
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MachineCodeForBasicBlock& MIVec,
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MachineCodeForBasicBlock::iterator& MII,
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const std::string& msg)
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{
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if (!IBef.empty())
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{
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MachineInstr* OrigMI = *MII;
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std::vector<MachineInstr *>::iterator AdIt;
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for (AdIt = IBef.begin(); AdIt != IBef.end() ; ++AdIt)
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{
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if (DEBUG_RA) {
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if (OrigMI) cerr << "For MInst:\n " << *OrigMI;
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cerr << msg << "PREPENDed instr:\n " << **AdIt << "\n";
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}
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MII = MIVec.insert(MII, *AdIt);
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++MII;
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}
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}
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}
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inline void
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AppendInstructions(std::vector<MachineInstr *> &IAft,
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MachineCodeForBasicBlock& MIVec,
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MachineCodeForBasicBlock::iterator& MII,
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const std::string& msg)
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{
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if (!IAft.empty())
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{
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MachineInstr* OrigMI = *MII;
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std::vector<MachineInstr *>::iterator AdIt;
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for ( AdIt = IAft.begin(); AdIt != IAft.end() ; ++AdIt )
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{
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if (DEBUG_RA) {
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if (OrigMI) cerr << "For MInst:\n " << *OrigMI;
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cerr << msg << "APPENDed instr:\n " << **AdIt << "\n";
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}
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++MII; // insert before the next instruction
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MII = MIVec.insert(MII, *AdIt);
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}
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}
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}
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void PhyRegAlloc::updateMachineCode()
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{
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MachineCodeForBasicBlock& MIVec = MachineCodeForBasicBlock::get(&Meth->getEntryNode());
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// Insert any instructions needed at method entry
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MachineCodeForBasicBlock::iterator MII = MIVec.begin();
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PrependInstructions(AddedInstrAtEntry.InstrnsBefore, MIVec, MII,
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"At function entry: \n");
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assert(AddedInstrAtEntry.InstrnsAfter.empty() &&
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"InstrsAfter should be unnecessary since we are just inserting at "
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"the function entry point here.");
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for (Function::const_iterator BBI = Meth->begin(), BBE = Meth->end();
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BBI != BBE; ++BBI) {
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// iterate over all the machine instructions in BB
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MachineCodeForBasicBlock &MIVec = MachineCodeForBasicBlock::get(BBI);
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for (MachineCodeForBasicBlock::iterator MII = MIVec.begin();
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MII != MIVec.end(); ++MII) {
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MachineInstr *MInst = *MII;
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unsigned Opcode = MInst->getOpCode();
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// do not process Phis
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if (TM.getInstrInfo().isDummyPhiInstr(Opcode))
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continue;
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// Reset tmp stack positions so they can be reused for each machine instr.
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mcInfo.popAllTempValues(TM);
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// Now insert speical instructions (if necessary) for call/return
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// instructions.
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//
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if (TM.getInstrInfo().isCall(Opcode) ||
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TM.getInstrInfo().isReturn(Opcode)) {
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|
|
AddedInstrns &AI = AddedInstrMap[MInst];
|
|
|
|
if (TM.getInstrInfo().isCall(Opcode))
|
|
MRI.colorCallArgs(MInst, LRI, &AI, *this, BBI);
|
|
else if (TM.getInstrInfo().isReturn(Opcode))
|
|
MRI.colorRetValue(MInst, LRI, &AI);
|
|
}
|
|
|
|
// Set the registers for operands in the machine instruction
|
|
// if a register was successfully allocated. If not, insert
|
|
// code to spill the register value.
|
|
//
|
|
for (unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum)
|
|
{
|
|
MachineOperand& Op = MInst->getOperand(OpNum);
|
|
if (Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
|
|
Op.getOperandType() == MachineOperand::MO_CCRegister)
|
|
{
|
|
const Value *const Val = Op.getVRegValue();
|
|
|
|
LiveRange *const LR = LRI.getLiveRangeForValue(Val);
|
|
if (!LR) // consts or labels will have no live range
|
|
{
|
|
// if register is not allocated, mark register as invalid
|
|
if (Op.getAllocatedRegNum() == -1)
|
|
MInst->SetRegForOperand(OpNum, MRI.getInvalidRegNum());
|
|
continue;
|
|
}
|
|
|
|
if (LR->hasColor() )
|
|
MInst->SetRegForOperand(OpNum,
|
|
MRI.getUnifiedRegNum(LR->getRegClass()->getID(),
|
|
LR->getColor()));
|
|
else
|
|
// LR did NOT receive a color (register). Insert spill code.
|
|
insertCode4SpilledLR(LR, MInst, BBI, OpNum );
|
|
}
|
|
} // for each operand
|
|
|
|
|
|
// Now add instructions that the register allocator inserts before/after
|
|
// this machine instructions (done only for calls/rets/incoming args)
|
|
// We do this here, to ensure that spill for an instruction is inserted
|
|
// closest as possible to an instruction (see above insertCode4Spill...)
|
|
//
|
|
// If there are instructions to be added, *before* this machine
|
|
// instruction, add them now.
|
|
//
|
|
if (AddedInstrMap.count(MInst)) {
|
|
PrependInstructions(AddedInstrMap[MInst].InstrnsBefore, MIVec, MII,"");
|
|
}
|
|
|
|
// If there are instructions to be added *after* this machine
|
|
// instruction, add them now
|
|
//
|
|
if (!AddedInstrMap[MInst].InstrnsAfter.empty()) {
|
|
|
|
// if there are delay slots for this instruction, the instructions
|
|
// added after it must really go after the delayed instruction(s)
|
|
// So, we move the InstrAfter of the current instruction to the
|
|
// corresponding delayed instruction
|
|
|
|
unsigned delay;
|
|
if ((delay=TM.getInstrInfo().getNumDelaySlots(MInst->getOpCode())) >0){
|
|
move2DelayedInstr(MInst, *(MII+delay) );
|
|
}
|
|
else {
|
|
// Here we can add the "instructions after" to the current
|
|
// instruction since there are no delay slots for this instruction
|
|
AppendInstructions(AddedInstrMap[MInst].InstrnsAfter, MIVec, MII,"");
|
|
} // if not delay
|
|
}
|
|
|
|
} // for each machine instruction
|
|
}
|
|
}
|
|
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// This method inserts spill code for AN operand whose LR was spilled.
|
|
// This method may be called several times for a single machine instruction
|
|
// if it contains many spilled operands. Each time it is called, 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 accomodate the spilled value.
|
|
//----------------------------------------------------------------------------
|
|
void PhyRegAlloc::insertCode4SpilledLR(const LiveRange *LR,
|
|
MachineInstr *MInst,
|
|
const BasicBlock *BB,
|
|
const unsigned OpNum) {
|
|
|
|
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 = MInst->operandIsDefined(OpNum);
|
|
bool isDefAndUse = MInst->operandIsDefinedAndUsed(OpNum);
|
|
unsigned RegType = MRI.getRegType( LR );
|
|
int SpillOff = LR->getSpillOffFromFP();
|
|
RegClass *RC = LR->getRegClass();
|
|
const ValueSet &LVSetBef = LVI->getLiveVarSetBeforeMInst(MInst, BB);
|
|
|
|
mcInfo.pushTempValue(TM, MRI.getSpilledRegSize(RegType) );
|
|
|
|
vector<MachineInstr*> MIBef, MIAft;
|
|
vector<MachineInstr*> AdIMid;
|
|
|
|
// Choose a register to hold the spilled value. This may insert code
|
|
// before and after MInst to free up the value. If so, this code should
|
|
// be first and last in the spill sequence before/after MInst.
|
|
int TmpRegU = 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).
|
|
int scratchRegType = -1;
|
|
int scratchReg = -1;
|
|
if (MRI.regTypeNeedsScratchReg(RegType, scratchRegType))
|
|
{
|
|
scratchReg = this->getUsableUniRegAtMI(scratchRegType, &LVSetBef,
|
|
MInst, MIBef, MIAft);
|
|
assert(scratchReg != MRI.getInvalidRegNum());
|
|
MInst->getRegsUsed().insert(scratchReg);
|
|
}
|
|
|
|
if (!isDef || isDefAndUse) {
|
|
// 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) {
|
|
cerr << "\nFor Inst:\n " << *MInst;
|
|
cerr << "SPILLED LR# " << LR->getUserIGNode()->getIndex();
|
|
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));
|
|
}
|
|
}
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// We can use the following method to get a temporary register to be used
|
|
// BEFORE any given machine instruction. If there is a register available,
|
|
// this method will simply return that register and set MIBef = MIAft = NULL.
|
|
// Otherwise, it will return a register and MIAft and MIBef will contain
|
|
// two instructions used to free up this returned register.
|
|
// Returned register number is the UNIFIED register number
|
|
//----------------------------------------------------------------------------
|
|
|
|
int PhyRegAlloc::getUsableUniRegAtMI(const int RegType,
|
|
const ValueSet *LVSetBef,
|
|
MachineInstr *MInst,
|
|
std::vector<MachineInstr*>& MIBef,
|
|
std::vector<MachineInstr*>& MIAft) {
|
|
|
|
RegClass* RC = this->getRegClassByID(MRI.getRegClassIDOfRegType(RegType));
|
|
|
|
int RegU = getUnusedUniRegAtMI(RC, 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 = mcInfo.pushTempValue(TM, MRI.getSpilledRegSize(RegType) );
|
|
|
|
RegU = getUniRegNotUsedByThisInst(RC, MInst);
|
|
|
|
// Check if we need a scratch register to copy this register to memory.
|
|
int scratchRegType = -1;
|
|
if (MRI.regTypeNeedsScratchReg(RegType, scratchRegType))
|
|
{
|
|
int scratchReg = this->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.
|
|
MInst->getRegsUsed().insert(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;
|
|
}
|
|
|
|
//----------------------------------------------------------------------------
|
|
// This method is called to get a new unused register that can be used to
|
|
// accomodate a spilled value.
|
|
// This method may be called several times for a single machine instruction
|
|
// if it contains many spilled operands. Each time it is called, 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.
|
|
// Return register number is relative to the register class. NOT
|
|
// unified number
|
|
//----------------------------------------------------------------------------
|
|
int PhyRegAlloc::getUnusedUniRegAtMI(RegClass *RC,
|
|
const MachineInstr *MInst,
|
|
const ValueSet *LVSetBef) {
|
|
|
|
unsigned NumAvailRegs = RC->getNumOfAvailRegs();
|
|
|
|
std::vector<bool> &IsColorUsedArr = RC->getIsColorUsedArr();
|
|
|
|
for (unsigned i=0; i < NumAvailRegs; i++) // Reset array
|
|
IsColorUsedArr[i] = false;
|
|
|
|
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
|
|
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() )
|
|
IsColorUsedArr[ LRofLV->getColor() ] = true;
|
|
}
|
|
|
|
// 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, MInst);
|
|
|
|
for (unsigned c=0; c < NumAvailRegs; c++) // find first unused color
|
|
if (!IsColorUsedArr[c])
|
|
return MRI.getUnifiedRegNum(RC->getID(), c);
|
|
|
|
return -1;
|
|
}
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// Get any other register in a register class, other than what is used
|
|
// by operands of a machine instruction. Returns the unified reg number.
|
|
//----------------------------------------------------------------------------
|
|
int PhyRegAlloc::getUniRegNotUsedByThisInst(RegClass *RC,
|
|
const MachineInstr *MInst) {
|
|
|
|
vector<bool> &IsColorUsedArr = RC->getIsColorUsedArr();
|
|
unsigned NumAvailRegs = RC->getNumOfAvailRegs();
|
|
|
|
for (unsigned i=0; i < NumAvailRegs ; i++) // Reset array
|
|
IsColorUsedArr[i] = false;
|
|
|
|
setRelRegsUsedByThisInst(RC, MInst);
|
|
|
|
for (unsigned c=0; c < RC->getNumOfAvailRegs(); c++)// find first unused color
|
|
if (!IsColorUsedArr[c])
|
|
return MRI.getUnifiedRegNum(RC->getID(), c);
|
|
|
|
assert(0 && "FATAL: No free register could be found in reg class!!");
|
|
return 0;
|
|
}
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// This method modifies the IsColorUsedArr of the register class passed to it.
|
|
// It sets the bits corresponding to the registers used by this machine
|
|
// instructions. Both explicit and implicit operands are set.
|
|
//----------------------------------------------------------------------------
|
|
void PhyRegAlloc::setRelRegsUsedByThisInst(RegClass *RC,
|
|
const MachineInstr *MInst ) {
|
|
|
|
vector<bool> &IsColorUsedArr = RC->getIsColorUsedArr();
|
|
|
|
// Add the registers already marked as used by the instruction.
|
|
// This should include any scratch registers that are used to save
|
|
// values across the instruction (e.g., for saving state register values).
|
|
const hash_set<int>& regsUsed = MInst->getRegsUsed();
|
|
for (hash_set<int>::const_iterator SI=regsUsed.begin(), SE=regsUsed.end();
|
|
SI != SE; ++SI)
|
|
{
|
|
unsigned classId = 0;
|
|
int classRegNum = MRI.getClassRegNum(*SI, classId);
|
|
if (RC->getID() == classId)
|
|
{
|
|
assert(classRegNum < (int) IsColorUsedArr.size() &&
|
|
"Illegal register number for this reg class?");
|
|
IsColorUsedArr[classRegNum] = true;
|
|
}
|
|
}
|
|
|
|
// Now add registers allocated to the live ranges of values used in
|
|
// the instruction. These are not yet recorded in the instruction.
|
|
for (unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum)
|
|
{
|
|
const MachineOperand& Op = MInst->getOperand(OpNum);
|
|
|
|
if (Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
|
|
Op.getOperandType() == MachineOperand::MO_CCRegister)
|
|
if (const Value* Val = Op.getVRegValue())
|
|
if (MRI.getRegClassIDOfValue(Val) == RC->getID())
|
|
if (Op.getAllocatedRegNum() == -1)
|
|
if (LiveRange *LROfVal = LRI.getLiveRangeForValue(Val))
|
|
if (LROfVal->hasColor() )
|
|
// this operand is in a LR that received a color
|
|
IsColorUsedArr[LROfVal->getColor()] = true;
|
|
}
|
|
|
|
// If there are implicit references, mark their allocated regs as well
|
|
//
|
|
for (unsigned z=0; z < MInst->getNumImplicitRefs(); z++)
|
|
if (const LiveRange*
|
|
LRofImpRef = LRI.getLiveRangeForValue(MInst->getImplicitRef(z)))
|
|
if (LRofImpRef->hasColor())
|
|
// this implicit reference is in a LR that received a color
|
|
IsColorUsedArr[LRofImpRef->getColor()] = true;
|
|
}
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// 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;
|
|
|
|
// "added instructions" of the delayed instr
|
|
AddedInstrns &DelayAdI = AddedInstrMap[DelayedMI];
|
|
|
|
// "added after" instructions of the delayed instr
|
|
std::vector<MachineInstr *> &DelayedAft = DelayAdI.InstrnsAfter;
|
|
|
|
// go thru all the "added after instructions" of the original instruction
|
|
// and append them to the "addded 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();
|
|
}
|
|
|
|
//----------------------------------------------------------------------------
|
|
// This method prints the code with registers after register allocation is
|
|
// complete.
|
|
//----------------------------------------------------------------------------
|
|
void PhyRegAlloc::printMachineCode()
|
|
{
|
|
|
|
cerr << "\n;************** Function " << Meth->getName()
|
|
<< " *****************\n";
|
|
|
|
for (Function::const_iterator BBI = Meth->begin(), BBE = Meth->end();
|
|
BBI != BBE; ++BBI) {
|
|
cerr << "\n"; printLabel(BBI); cerr << ": ";
|
|
|
|
// get the iterator for machine instructions
|
|
MachineCodeForBasicBlock& MIVec = MachineCodeForBasicBlock::get(BBI);
|
|
MachineCodeForBasicBlock::iterator MII = MIVec.begin();
|
|
|
|
// iterate over all the machine instructions in BB
|
|
for ( ; MII != MIVec.end(); ++MII) {
|
|
MachineInstr *const MInst = *MII;
|
|
|
|
cerr << "\n\t";
|
|
cerr << TargetInstrDescriptors[MInst->getOpCode()].opCodeString;
|
|
|
|
for (unsigned OpNum=0; OpNum < MInst->getNumOperands(); ++OpNum) {
|
|
MachineOperand& Op = MInst->getOperand(OpNum);
|
|
|
|
if (Op.getOperandType() == MachineOperand::MO_VirtualRegister ||
|
|
Op.getOperandType() == MachineOperand::MO_CCRegister /*||
|
|
Op.getOperandType() == MachineOperand::MO_PCRelativeDisp*/ ) {
|
|
|
|
const Value *const Val = Op.getVRegValue () ;
|
|
// ****this code is temporary till NULL Values are fixed
|
|
if (! Val ) {
|
|
cerr << "\t<*NULL*>";
|
|
continue;
|
|
}
|
|
|
|
// if a label or a constant
|
|
if (isa<BasicBlock>(Val)) {
|
|
cerr << "\t"; printLabel( Op.getVRegValue () );
|
|
} else {
|
|
// else it must be a register value
|
|
const int RegNum = Op.getAllocatedRegNum();
|
|
|
|
cerr << "\t" << "%" << MRI.getUnifiedRegName( RegNum );
|
|
if (Val->hasName() )
|
|
cerr << "(" << Val->getName() << ")";
|
|
else
|
|
cerr << "(" << Val << ")";
|
|
|
|
if (Op.opIsDef() )
|
|
cerr << "*";
|
|
|
|
const LiveRange *LROfVal = LRI.getLiveRangeForValue(Val);
|
|
if (LROfVal )
|
|
if (LROfVal->hasSpillOffset() )
|
|
cerr << "$";
|
|
}
|
|
|
|
}
|
|
else if (Op.getOperandType() == MachineOperand::MO_MachineRegister) {
|
|
cerr << "\t" << "%" << MRI.getUnifiedRegName(Op.getMachineRegNum());
|
|
}
|
|
|
|
else
|
|
cerr << "\t" << Op; // use dump field
|
|
}
|
|
|
|
|
|
|
|
unsigned NumOfImpRefs = MInst->getNumImplicitRefs();
|
|
if (NumOfImpRefs > 0) {
|
|
cerr << "\tImplicit:";
|
|
|
|
for (unsigned z=0; z < NumOfImpRefs; z++)
|
|
cerr << RAV(MInst->getImplicitRef(z)) << "\t";
|
|
}
|
|
|
|
} // for all machine instructions
|
|
|
|
cerr << "\n";
|
|
|
|
} // for all BBs
|
|
|
|
cerr << "\n";
|
|
}
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
|
|
//----------------------------------------------------------------------------
|
|
void PhyRegAlloc::colorIncomingArgs()
|
|
{
|
|
const BasicBlock &FirstBB = Meth->front();
|
|
const MachineInstr *FirstMI = MachineCodeForBasicBlock::get(&FirstBB).front();
|
|
assert(FirstMI && "No machine instruction in entry BB");
|
|
|
|
MRI.colorMethodArgs(Meth, LRI, &AddedInstrAtEntry);
|
|
}
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// Used to generate a label for a basic block
|
|
//----------------------------------------------------------------------------
|
|
void PhyRegAlloc::printLabel(const Value *const Val) {
|
|
if (Val->hasName())
|
|
cerr << Val->getName();
|
|
else
|
|
cerr << "Label" << Val;
|
|
}
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// This method calls setSugColorUsable method of each live range. This
|
|
// will determine whether the suggested color of LR is really usable.
|
|
// A suggested color is not usable when the suggested color is volatile
|
|
// AND when there are call interferences
|
|
//----------------------------------------------------------------------------
|
|
|
|
void PhyRegAlloc::markUnusableSugColors()
|
|
{
|
|
// hash map iterator
|
|
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 (L->hasSuggestedColor()) {
|
|
int RCID = L->getRegClass()->getID();
|
|
if (MRI.isRegVolatile( RCID, L->getSuggestedColor()) &&
|
|
L->isCallInterference() )
|
|
L->setSuggestedColorUsable( false );
|
|
else
|
|
L->setSuggestedColorUsable( true );
|
|
}
|
|
} // if L->hasSuggestedColor()
|
|
}
|
|
} // for all LR's in hash map
|
|
}
|
|
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// The following method will set the stack offsets of the live ranges that
|
|
// are decided to be spillled. This must be called just after coloring the
|
|
// LRs using the graph coloring algo. For each live range that is spilled,
|
|
// this method allocate a new spill position on the stack.
|
|
//----------------------------------------------------------------------------
|
|
|
|
void PhyRegAlloc::allocateStackSpace4SpilledLRs() {
|
|
if (DEBUG_RA) 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->hasColor()) { // NOTE: ** allocating the size of long Type **
|
|
int stackOffset = mcInfo.allocateSpilledValue(TM, Type::LongTy);
|
|
L->setSpillOffFromFP(stackOffset);
|
|
if (DEBUG_RA)
|
|
cerr << " LR# " << L->getUserIGNode()->getIndex()
|
|
<< ": stack-offset = " << stackOffset << "\n";
|
|
}
|
|
}
|
|
} // for all LR's in hash map
|
|
}
|
|
|
|
|
|
|
|
//----------------------------------------------------------------------------
|
|
// The entry pont to Register Allocation
|
|
//----------------------------------------------------------------------------
|
|
|
|
void PhyRegAlloc::allocateRegisters()
|
|
{
|
|
|
|
// make sure that we put all register classes into the RegClassList
|
|
// before we call constructLiveRanges (now done in the constructor of
|
|
// PhyRegAlloc class).
|
|
//
|
|
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();
|
|
|
|
// Atter grpah coloring, if some LRs did not receive a color (i.e, spilled)
|
|
// a poistion for such spilled LRs
|
|
//
|
|
allocateStackSpace4SpilledLRs();
|
|
|
|
mcInfo.popAllTempValues(TM); // TODO **Check
|
|
|
|
// color incoming args - if the correct color was not received
|
|
// insert code to copy to the correct register
|
|
//
|
|
colorIncomingArgs();
|
|
|
|
// 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) {
|
|
cerr << "\n**** Machine Code After Register Allocation:\n\n";
|
|
MachineCodeForMethod::get(Meth).dump();
|
|
}
|
|
}
|
|
|
|
|
|
|