+
+void MachineBasicBlock::addPredecessor(MachineBasicBlock *pred) {
+ Predecessors.push_back(pred);
+}
+
+void MachineBasicBlock::removePredecessor(MachineBasicBlock *pred) {
+ std::vector<MachineBasicBlock *>::iterator I =
+ std::find(Predecessors.begin(), Predecessors.end(), pred);
+ assert(I != Predecessors.end() && "Pred is not a predecessor of this block!");
+ Predecessors.erase(I);
+}
+
+void MachineBasicBlock::transferSuccessors(MachineBasicBlock *fromMBB) {
+ if (this == fromMBB)
+ return;
+
+ for (MachineBasicBlock::succ_iterator I = fromMBB->succ_begin(),
+ E = fromMBB->succ_end(); I != E; ++I)
+ addSuccessor(*I);
+
+ while (!fromMBB->succ_empty())
+ fromMBB->removeSuccessor(fromMBB->succ_begin());
+}
+
+bool MachineBasicBlock::isSuccessor(const MachineBasicBlock *MBB) const {
+ std::vector<MachineBasicBlock *>::const_iterator I =
+ std::find(Successors.begin(), Successors.end(), MBB);
+ return I != Successors.end();
+}
+
+bool MachineBasicBlock::isLayoutSuccessor(const MachineBasicBlock *MBB) const {
+ MachineFunction::const_iterator I(this);
+ return llvm::next(I) == MachineFunction::const_iterator(MBB);
+}
+
+bool MachineBasicBlock::canFallThrough() {
+ MachineFunction::iterator Fallthrough = this;
+ ++Fallthrough;
+ // If FallthroughBlock is off the end of the function, it can't fall through.
+ if (Fallthrough == getParent()->end())
+ return false;
+
+ // If FallthroughBlock isn't a successor, no fallthrough is possible.
+ if (!isSuccessor(Fallthrough))
+ return false;
+
+ // Analyze the branches, if any, at the end of the block.
+ MachineBasicBlock *TBB = 0, *FBB = 0;
+ SmallVector<MachineOperand, 4> Cond;
+ const TargetInstrInfo *TII = getParent()->getTarget().getInstrInfo();
+ if (TII->AnalyzeBranch(*this, TBB, FBB, Cond)) {
+ // If we couldn't analyze the branch, examine the last instruction.
+ // If the block doesn't end in a known control barrier, assume fallthrough
+ // is possible. The isPredicable check is needed because this code can be
+ // called during IfConversion, where an instruction which is normally a
+ // Barrier is predicated and thus no longer an actual control barrier. This
+ // is over-conservative though, because if an instruction isn't actually
+ // predicated we could still treat it like a barrier.
+ return empty() || !back().getDesc().isBarrier() ||
+ back().getDesc().isPredicable();
+ }
+
+ // If there is no branch, control always falls through.
+ if (TBB == 0) return true;
+
+ // If there is some explicit branch to the fallthrough block, it can obviously
+ // reach, even though the branch should get folded to fall through implicitly.
+ if (MachineFunction::iterator(TBB) == Fallthrough ||
+ MachineFunction::iterator(FBB) == Fallthrough)
+ return true;
+
+ // If it's an unconditional branch to some block not the fall through, it
+ // doesn't fall through.
+ if (Cond.empty()) return false;
+
+ // Otherwise, if it is conditional and has no explicit false block, it falls
+ // through.
+ return FBB == 0;
+}
+
+/// removeFromParent - This method unlinks 'this' from the containing function,
+/// and returns it, but does not delete it.
+MachineBasicBlock *MachineBasicBlock::removeFromParent() {
+ assert(getParent() && "Not embedded in a function!");
+ getParent()->remove(this);
+ return this;
+}
+
+
+/// eraseFromParent - This method unlinks 'this' from the containing function,
+/// and deletes it.
+void MachineBasicBlock::eraseFromParent() {
+ assert(getParent() && "Not embedded in a function!");
+ getParent()->erase(this);
+}
+
+
+/// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
+/// 'Old', change the code and CFG so that it branches to 'New' instead.
+void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old,
+ MachineBasicBlock *New) {
+ assert(Old != New && "Cannot replace self with self!");
+
+ MachineBasicBlock::iterator I = end();
+ while (I != begin()) {
+ --I;
+ if (!I->getDesc().isTerminator()) break;
+
+ // Scan the operands of this machine instruction, replacing any uses of Old
+ // with New.
+ for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
+ if (I->getOperand(i).isMBB() &&
+ I->getOperand(i).getMBB() == Old)
+ I->getOperand(i).setMBB(New);
+ }
+
+ // Update the successor information.
+ removeSuccessor(Old);
+ addSuccessor(New);
+}
+
+/// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in the
+/// CFG to be inserted. If we have proven that MBB can only branch to DestA and
+/// DestB, remove any other MBB successors from the CFG. DestA and DestB can be
+/// null.
+///
+/// Besides DestA and DestB, retain other edges leading to LandingPads
+/// (currently there can be only one; we don't check or require that here).
+/// Note it is possible that DestA and/or DestB are LandingPads.
+bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA,
+ MachineBasicBlock *DestB,
+ bool isCond) {
+ // The values of DestA and DestB frequently come from a call to the
+ // 'TargetInstrInfo::AnalyzeBranch' method. We take our meaning of the initial
+ // values from there.
+ //
+ // 1. If both DestA and DestB are null, then the block ends with no branches
+ // (it falls through to its successor).
+ // 2. If DestA is set, DestB is null, and isCond is false, then the block ends
+ // with only an unconditional branch.
+ // 3. If DestA is set, DestB is null, and isCond is true, then the block ends
+ // with a conditional branch that falls through to a successor (DestB).
+ // 4. If DestA and DestB is set and isCond is true, then the block ends with a
+ // conditional branch followed by an unconditional branch. DestA is the
+ // 'true' destination and DestB is the 'false' destination.
+
+ bool MadeChange = false;
+ bool AddedFallThrough = false;
+
+ MachineFunction::iterator FallThru =
+ llvm::next(MachineFunction::iterator(this));
+
+ if (isCond) {
+ // If this block ends with a conditional branch that falls through to its
+ // successor, set DestB as the successor.
+ if (DestB == 0 && FallThru != getParent()->end()) {
+ DestB = FallThru;
+ AddedFallThrough = true;
+ }
+ } else {
+ // If this is an unconditional branch with no explicit dest, it must just be
+ // a fallthrough into DestA.
+ if (DestA == 0 && FallThru != getParent()->end()) {
+ DestA = FallThru;
+ AddedFallThrough = true;
+ }
+ }
+
+ MachineBasicBlock::succ_iterator SI = succ_begin();
+ MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
+ while (SI != succ_end()) {
+ const MachineBasicBlock *MBB = *SI;
+ if (MBB == DestA) {
+ DestA = 0;
+ ++SI;
+ } else if (MBB == DestB) {
+ DestB = 0;
+ ++SI;
+ } else if (MBB->isLandingPad() &&
+ MBB != OrigDestA && MBB != OrigDestB) {
+ ++SI;
+ } else {
+ // Otherwise, this is a superfluous edge, remove it.
+ SI = removeSuccessor(SI);
+ MadeChange = true;
+ }
+ }
+
+ if (!AddedFallThrough)
+ assert(DestA == 0 && DestB == 0 && "MachineCFG is missing edges!");
+ else if (isCond)
+ assert(DestA == 0 && "MachineCFG is missing edges!");
+
+ return MadeChange;
+}
+
+/// findDebugLoc - find the next valid DebugLoc starting at MBBI, skipping
+/// any DBG_VALUE instructions. Return UnknownLoc if there is none.
+DebugLoc
+MachineBasicBlock::findDebugLoc(MachineBasicBlock::iterator &MBBI) {
+ DebugLoc DL;
+ MachineBasicBlock::iterator E = end();
+ if (MBBI != E) {
+ // Skip debug declarations, we don't want a DebugLoc from them.
+ MachineBasicBlock::iterator MBBI2 = MBBI;
+ while (MBBI2 != E && MBBI2->isDebugValue())
+ MBBI2++;
+ if (MBBI2 != E)
+ DL = MBBI2->getDebugLoc();
+ }
+ return DL;
+}
+
+void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB,
+ bool t) {
+ OS << "BB#" << MBB->getNumber();
+}
+