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llvm-mirror/lib/CodeGen/MachineLoopInfo.cpp
Owen Anderson 63f757463c Begin adding static dependence information to passes, which will allow us to
perform initialization without static constructors AND without explicit initialization
by the client.  For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve.  I hope to be able to relax
the latter requirement in the future.

llvm-svn: 116334
2010-10-12 19:48:12 +00:00

84 lines
2.8 KiB
C++

//===- MachineLoopInfo.cpp - Natural Loop Calculator ----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the MachineLoopInfo class that is used to identify natural
// loops and determine the loop depth of various nodes of the CFG. Note that
// the loops identified may actually be several natural loops that share the
// same header node... not just a single natural loop.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
namespace llvm {
#define MLB class LoopBase<MachineBasicBlock, MachineLoop>
TEMPLATE_INSTANTIATION(MLB);
#undef MLB
#define MLIB class LoopInfoBase<MachineBasicBlock, MachineLoop>
TEMPLATE_INSTANTIATION(MLIB);
#undef MLIB
}
char MachineLoopInfo::ID = 0;
INITIALIZE_PASS_BEGIN(MachineLoopInfo, "machine-loops",
"Machine Natural Loop Construction", true, true)
INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
INITIALIZE_PASS_END(MachineLoopInfo, "machine-loops",
"Machine Natural Loop Construction", true, true)
char &llvm::MachineLoopInfoID = MachineLoopInfo::ID;
bool MachineLoopInfo::runOnMachineFunction(MachineFunction &) {
releaseMemory();
LI.Calculate(getAnalysis<MachineDominatorTree>().getBase()); // Update
return false;
}
void MachineLoopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<MachineDominatorTree>();
MachineFunctionPass::getAnalysisUsage(AU);
}
MachineBasicBlock *MachineLoop::getTopBlock() {
MachineBasicBlock *TopMBB = getHeader();
MachineFunction::iterator Begin = TopMBB->getParent()->begin();
if (TopMBB != Begin) {
MachineBasicBlock *PriorMBB = prior(MachineFunction::iterator(TopMBB));
while (contains(PriorMBB)) {
TopMBB = PriorMBB;
if (TopMBB == Begin) break;
PriorMBB = prior(MachineFunction::iterator(TopMBB));
}
}
return TopMBB;
}
MachineBasicBlock *MachineLoop::getBottomBlock() {
MachineBasicBlock *BotMBB = getHeader();
MachineFunction::iterator End = BotMBB->getParent()->end();
if (BotMBB != prior(End)) {
MachineBasicBlock *NextMBB = llvm::next(MachineFunction::iterator(BotMBB));
while (contains(NextMBB)) {
BotMBB = NextMBB;
if (BotMBB == llvm::next(MachineFunction::iterator(BotMBB))) break;
NextMBB = llvm::next(MachineFunction::iterator(BotMBB));
}
}
return BotMBB;
}
void MachineLoop::dump() const {
print(dbgs());
}