llvm-6502/lib/CodeGen/PostRASchedulerList.cpp

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//===----- SchedulePostRAList.cpp - list scheduler ------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Dale Johannesen and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements a top-down list scheduler, using standard algorithms.
// The basic approach uses a priority queue of available nodes to schedule.
// One at a time, nodes are taken from the priority queue (thus in priority
// order), checked for legality to schedule, and emitted if legal.
//
// Nodes may not be legal to schedule either due to structural hazards (e.g.
// pipeline or resource constraints) or because an input to the instruction has
// not completed execution.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "post-RA-sched"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/Support/Debug.h"
//#include "llvm/ADT/Statistic.h"
//#include <climits>
//#include <queue>
#include "llvm/Support/CommandLine.h"
using namespace llvm;
namespace {
bool NoPostRAScheduling;
// When this works it will be on by default.
cl::opt<bool, true>
DisablePostRAScheduler("disable-post-RA-scheduler",
cl::desc("Disable scheduling after register allocation"),
cl::location(NoPostRAScheduling),
cl::init(true));
class VISIBILITY_HIDDEN SchedulePostRATDList : public MachineFunctionPass {
public:
static char ID;
SchedulePostRATDList() : MachineFunctionPass((intptr_t)&ID) {}
private:
MachineFunction *MF;
const TargetMachine *TM;
public:
const char *getPassName() const {
return "Post RA top-down list latency scheduler (STUB)";
}
bool runOnMachineFunction(MachineFunction &Fn);
};
char SchedulePostRATDList::ID = 0;
}
bool SchedulePostRATDList::runOnMachineFunction(MachineFunction &Fn) {
if (NoPostRAScheduling)
return true;
DOUT << "SchedulePostRATDList\n";
MF = &Fn;
TM = &MF->getTarget();
// Loop over all of the basic blocks
for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end();
MBB != MBBe; ++MBB)
;
return true;
}
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
FunctionPass *llvm::createPostRAScheduler() {
return new SchedulePostRATDList();
}