1 //===-- llvm/CodeGen/MachineBasicBlock.cpp ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Collect the sequence of machine instructions for a basic block.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/MachineBasicBlock.h"
15 #include "llvm/BasicBlock.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/Target/TargetRegisterInfo.h"
18 #include "llvm/Target/TargetData.h"
19 #include "llvm/Target/TargetInstrDesc.h"
20 #include "llvm/Target/TargetMachine.h"
21 #include "llvm/Support/LeakDetector.h"
25 MachineBasicBlock::MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb)
26 : BB(bb), Number(-1), xParent(&mf), Alignment(0), IsLandingPad(false) {
30 MachineBasicBlock::~MachineBasicBlock() {
31 LeakDetector::removeGarbageObject(this);
34 std::ostream& llvm::operator<<(std::ostream &OS, const MachineBasicBlock &MBB) {
39 /// addNodeToList (MBB) - When an MBB is added to an MF, we need to update the
40 /// parent pointer of the MBB, the MBB numbering, and any instructions in the
41 /// MBB to be on the right operand list for registers.
43 /// MBBs start out as #-1. When a MBB is added to a MachineFunction, it
44 /// gets the next available unique MBB number. If it is removed from a
45 /// MachineFunction, it goes back to being #-1.
46 void ilist_traits<MachineBasicBlock>::addNodeToList(MachineBasicBlock* N) {
47 MachineFunction &MF = *N->getParent();
48 N->Number = MF.addToMBBNumbering(N);
50 // Make sure the instructions have their operands in the reginfo lists.
51 MachineRegisterInfo &RegInfo = MF.getRegInfo();
52 for (MachineBasicBlock::iterator I = N->begin(), E = N->end(); I != E; ++I)
53 I->AddRegOperandsToUseLists(RegInfo);
55 LeakDetector::removeGarbageObject(N);
58 void ilist_traits<MachineBasicBlock>::removeNodeFromList(MachineBasicBlock* N) {
59 N->getParent()->removeFromMBBNumbering(N->Number);
61 LeakDetector::addGarbageObject(N);
65 /// addNodeToList (MI) - When we add an instruction to a basic block
66 /// list, we update its parent pointer and add its operands from reg use/def
67 /// lists if appropriate.
68 void ilist_traits<MachineInstr>::addNodeToList(MachineInstr* N) {
69 assert(N->getParent() == 0 && "machine instruction already in a basic block");
72 // Add the instruction's register operands to their corresponding
74 MachineFunction *MF = Parent->getParent();
75 N->AddRegOperandsToUseLists(MF->getRegInfo());
77 LeakDetector::removeGarbageObject(N);
80 /// removeNodeFromList (MI) - When we remove an instruction from a basic block
81 /// list, we update its parent pointer and remove its operands from reg use/def
82 /// lists if appropriate.
83 void ilist_traits<MachineInstr>::removeNodeFromList(MachineInstr* N) {
84 assert(N->getParent() != 0 && "machine instruction not in a basic block");
86 // Remove from the use/def lists.
87 N->RemoveRegOperandsFromUseLists();
91 LeakDetector::addGarbageObject(N);
94 /// transferNodesFromList (MI) - When moving a range of instructions from one
95 /// MBB list to another, we need to update the parent pointers and the use/def
97 void ilist_traits<MachineInstr>::transferNodesFromList(
98 ilist_traits<MachineInstr>& fromList,
99 MachineBasicBlock::iterator first,
100 MachineBasicBlock::iterator last) {
101 assert(Parent->getParent() == fromList.Parent->getParent() &&
102 "MachineInstr parent mismatch!");
104 // Splice within the same MBB -> no change.
105 if (Parent == fromList.Parent) return;
107 // If splicing between two blocks within the same function, just update the
109 for (; first != last; ++first)
110 first->setParent(Parent);
113 void ilist_traits<MachineInstr>::deleteNode(MachineInstr* MI) {
114 assert(!MI->getParent() && "MI is still in a block!");
115 Parent->getParent()->DeleteMachineInstr(MI);
118 MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
120 while (I != begin() && (--I)->getDesc().isTerminator())
122 if (I != end() && !I->getDesc().isTerminator()) ++I;
126 void MachineBasicBlock::dump() const {
127 print(*cerr.stream());
130 static inline void OutputReg(std::ostream &os, unsigned RegNo,
131 const TargetRegisterInfo *TRI = 0) {
132 if (!RegNo || TargetRegisterInfo::isPhysicalRegister(RegNo)) {
134 os << " %" << TRI->get(RegNo).Name;
136 os << " %mreg(" << RegNo << ")";
138 os << " %reg" << RegNo;
141 void MachineBasicBlock::print(std::ostream &OS) const {
142 const MachineFunction *MF = getParent();
144 OS << "Can't print out MachineBasicBlock because parent MachineFunction"
149 const BasicBlock *LBB = getBasicBlock();
151 if (LBB) OS << LBB->getName() << ": ";
152 OS << (const void*)this
153 << ", LLVM BB @" << (const void*) LBB << ", ID#" << getNumber();
154 if (Alignment) OS << ", Alignment " << Alignment;
155 if (isLandingPad()) OS << ", EH LANDING PAD";
158 const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
159 if (!livein_empty()) {
161 for (const_livein_iterator I = livein_begin(),E = livein_end(); I != E; ++I)
162 OutputReg(OS, *I, TRI);
165 // Print the preds of this block according to the CFG.
167 OS << " Predecessors according to CFG:";
168 for (const_pred_iterator PI = pred_begin(), E = pred_end(); PI != E; ++PI)
169 OS << " " << *PI << " (#" << (*PI)->getNumber() << ")";
173 for (const_iterator I = begin(); I != end(); ++I) {
175 I->print(OS, &getParent()->getTarget());
178 // Print the successors of this block according to the CFG.
180 OS << " Successors according to CFG:";
181 for (const_succ_iterator SI = succ_begin(), E = succ_end(); SI != E; ++SI)
182 OS << " " << *SI << " (#" << (*SI)->getNumber() << ")";
187 void MachineBasicBlock::removeLiveIn(unsigned Reg) {
188 livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
189 assert(I != livein_end() && "Not a live in!");
193 bool MachineBasicBlock::isLiveIn(unsigned Reg) const {
194 const_livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
195 return I != livein_end();
198 void MachineBasicBlock::moveBefore(MachineBasicBlock *NewAfter) {
199 getParent()->splice(NewAfter, this);
202 void MachineBasicBlock::moveAfter(MachineBasicBlock *NewBefore) {
203 MachineFunction::iterator BBI = NewBefore;
204 getParent()->splice(++BBI, this);
208 void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ) {
209 Successors.push_back(succ);
210 succ->addPredecessor(this);
213 void MachineBasicBlock::removeSuccessor(MachineBasicBlock *succ) {
214 succ->removePredecessor(this);
215 succ_iterator I = std::find(Successors.begin(), Successors.end(), succ);
216 assert(I != Successors.end() && "Not a current successor!");
220 MachineBasicBlock::succ_iterator
221 MachineBasicBlock::removeSuccessor(succ_iterator I) {
222 assert(I != Successors.end() && "Not a current successor!");
223 (*I)->removePredecessor(this);
224 return Successors.erase(I);
227 void MachineBasicBlock::addPredecessor(MachineBasicBlock *pred) {
228 Predecessors.push_back(pred);
231 void MachineBasicBlock::removePredecessor(MachineBasicBlock *pred) {
232 std::vector<MachineBasicBlock *>::iterator I =
233 std::find(Predecessors.begin(), Predecessors.end(), pred);
234 assert(I != Predecessors.end() && "Pred is not a predecessor of this block!");
235 Predecessors.erase(I);
238 void MachineBasicBlock::transferSuccessors(MachineBasicBlock *fromMBB)
243 for(MachineBasicBlock::succ_iterator iter = fromMBB->succ_begin(),
244 end = fromMBB->succ_end(); iter != end; ++iter) {
247 while(!fromMBB->succ_empty())
248 fromMBB->removeSuccessor(fromMBB->succ_begin());
251 bool MachineBasicBlock::isSuccessor(MachineBasicBlock *MBB) const {
252 std::vector<MachineBasicBlock *>::const_iterator I =
253 std::find(Successors.begin(), Successors.end(), MBB);
254 return I != Successors.end();
257 bool MachineBasicBlock::isLayoutSuccessor(MachineBasicBlock *MBB) const {
258 MachineFunction::const_iterator I(this);
259 return next(I) == MachineFunction::const_iterator(MBB);
262 /// removeFromParent - This method unlinks 'this' from the containing function,
263 /// and returns it, but does not delete it.
264 MachineBasicBlock *MachineBasicBlock::removeFromParent() {
265 assert(getParent() && "Not embedded in a function!");
266 getParent()->remove(this);
271 /// eraseFromParent - This method unlinks 'this' from the containing function,
273 void MachineBasicBlock::eraseFromParent() {
274 assert(getParent() && "Not embedded in a function!");
275 getParent()->erase(this);
279 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
280 /// 'Old', change the code and CFG so that it branches to 'New' instead.
281 void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old,
282 MachineBasicBlock *New) {
283 assert(Old != New && "Cannot replace self with self!");
285 MachineBasicBlock::iterator I = end();
286 while (I != begin()) {
288 if (!I->getDesc().isTerminator()) break;
290 // Scan the operands of this machine instruction, replacing any uses of Old
292 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
293 if (I->getOperand(i).isMBB() &&
294 I->getOperand(i).getMBB() == Old)
295 I->getOperand(i).setMBB(New);
298 // Update the successor information. If New was already a successor, just
299 // remove the link to Old instead of creating another one. PR 1444.
300 removeSuccessor(Old);
301 if (!isSuccessor(New))
305 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in the
306 /// CFG to be inserted. If we have proven that MBB can only branch to DestA and
307 /// DestB, remove any other MBB successors from the CFG. DestA and DestB can
309 /// Besides DestA and DestB, retain other edges leading to LandingPads
310 /// (currently there can be only one; we don't check or require that here).
311 /// Note it is possible that DestA and/or DestB are LandingPads.
312 bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA,
313 MachineBasicBlock *DestB,
315 bool MadeChange = false;
316 bool AddedFallThrough = false;
318 MachineFunction::iterator FallThru = next(MachineFunction::iterator(this));
320 // If this block ends with a conditional branch that falls through to its
321 // successor, set DestB as the successor.
323 if (DestB == 0 && FallThru != getParent()->end()) {
325 AddedFallThrough = true;
328 // If this is an unconditional branch with no explicit dest, it must just be
329 // a fallthrough into DestB.
330 if (DestA == 0 && FallThru != getParent()->end()) {
332 AddedFallThrough = true;
336 MachineBasicBlock::succ_iterator SI = succ_begin();
337 MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
338 while (SI != succ_end()) {
339 if (*SI == DestA && DestA == DestB) {
342 } else if (*SI == DestA) {
345 } else if (*SI == DestB) {
348 } else if ((*SI)->isLandingPad() &&
349 *SI!=OrigDestA && *SI!=OrigDestB) {
352 // Otherwise, this is a superfluous edge, remove it.
353 SI = removeSuccessor(SI);
357 if (!AddedFallThrough) {
358 assert(DestA == 0 && DestB == 0 &&
359 "MachineCFG is missing edges!");
361 assert(DestA == 0 && "MachineCFG is missing edges!");