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() {
26 LeakDetector::removeGarbageObject(this);
29 std::ostream& llvm::operator<<(std::ostream &OS, const MachineBasicBlock &MBB) {
34 /// addNodeToList (MBB) - When an MBB is added to an MF, we need to update the
35 /// parent pointer of the MBB, the MBB numbering, and any instructions in the
36 /// MBB to be on the right operand list for registers.
38 /// MBBs start out as #-1. When a MBB is added to a MachineFunction, it
39 /// gets the next available unique MBB number. If it is removed from a
40 /// MachineFunction, it goes back to being #-1.
41 void ilist_traits<MachineBasicBlock>::addNodeToList(MachineBasicBlock* N) {
42 assert(N->getParent() == 0 && "machine instruction already in a basic block");
44 N->Number = Parent->addToMBBNumbering(N);
46 // Make sure the instructions have their operands in the reginfo lists.
47 MachineRegisterInfo &RegInfo = Parent->getRegInfo();
48 for (MachineBasicBlock::iterator I = N->begin(), E = N->end(); I != E; ++I)
49 I->AddRegOperandsToUseLists(RegInfo);
51 LeakDetector::removeGarbageObject(N);
54 void ilist_traits<MachineBasicBlock>::removeNodeFromList(MachineBasicBlock* N) {
55 assert(N->getParent() != 0 && "machine instruction not in a basic block");
56 N->getParent()->removeFromMBBNumbering(N->Number);
60 // Make sure the instructions have their operands removed from the reginfo
62 for (MachineBasicBlock::iterator I = N->begin(), E = N->end(); I != E; ++I)
63 I->RemoveRegOperandsFromUseLists();
65 LeakDetector::addGarbageObject(N);
69 MachineInstr* ilist_traits<MachineInstr>::createSentinel() {
70 MachineInstr* dummy = new MachineInstr();
71 LeakDetector::removeGarbageObject(dummy);
75 /// addNodeToList (MI) - When we add an instruction to a basic block
76 /// list, we update its parent pointer and add its operands from reg use/def
77 /// lists if appropriate.
78 void ilist_traits<MachineInstr>::addNodeToList(MachineInstr* N) {
79 assert(N->getParent() == 0 && "machine instruction already in a basic block");
81 LeakDetector::removeGarbageObject(N);
83 // If the block is in a function, add the instruction's register operands to
84 // their corresponding use/def lists.
85 if (MachineFunction *MF = parent->getParent())
86 N->AddRegOperandsToUseLists(MF->getRegInfo());
89 /// removeNodeFromList (MI) - When we remove an instruction from a basic block
90 /// list, we update its parent pointer and remove its operands from reg use/def
91 /// lists if appropriate.
92 void ilist_traits<MachineInstr>::removeNodeFromList(MachineInstr* N) {
93 assert(N->getParent() != 0 && "machine instruction not in a basic block");
94 // If this block is in a function, remove from the use/def lists.
95 if (parent->getParent() != 0)
96 N->RemoveRegOperandsFromUseLists();
99 LeakDetector::addGarbageObject(N);
102 /// transferNodesFromList (MI) - When moving a range of instructions from one
103 /// MBB list to another, we need to update the parent pointers and the use/def
105 void ilist_traits<MachineInstr>::transferNodesFromList(
106 iplist<MachineInstr, ilist_traits<MachineInstr> >& fromList,
107 ilist_iterator<MachineInstr> first,
108 ilist_iterator<MachineInstr> last) {
109 // Splice within the same MBB -> no change.
110 if (parent == fromList.parent) return;
112 // If splicing between two blocks within the same function, just update the
114 if (parent->getParent() == fromList.parent->getParent()) {
115 for (; first != last; ++first)
116 first->setParent(parent);
120 // Otherwise, we have to update the parent and the use/def lists. The common
121 // case when this occurs is if we're splicing from a block in a MF to a block
122 // that is not in an MF.
123 bool HasOldMF = fromList.parent->getParent() != 0;
124 MachineFunction *NewMF = parent->getParent();
126 for (; first != last; ++first) {
127 if (HasOldMF) first->RemoveRegOperandsFromUseLists();
128 first->setParent(parent);
129 if (NewMF) first->AddRegOperandsToUseLists(NewMF->getRegInfo());
133 MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
135 while (I != begin() && (--I)->getDesc().isTerminator())
137 if (I != end() && !I->getDesc().isTerminator()) ++I;
141 void MachineBasicBlock::dump() const {
142 print(*cerr.stream());
145 static inline void OutputReg(std::ostream &os, unsigned RegNo,
146 const TargetRegisterInfo *TRI = 0) {
147 if (!RegNo || TargetRegisterInfo::isPhysicalRegister(RegNo)) {
149 os << " %" << TRI->get(RegNo).PrintableName;
151 os << " %mreg(" << RegNo << ")";
153 os << " %reg" << RegNo;
156 void MachineBasicBlock::print(std::ostream &OS) const {
157 const MachineFunction *MF = getParent();
159 OS << "Can't print out MachineBasicBlock because parent MachineFunction"
164 const BasicBlock *LBB = getBasicBlock();
166 if (LBB) OS << LBB->getName() << ": ";
167 OS << (const void*)this
168 << ", LLVM BB @" << (const void*) LBB << ", ID#" << getNumber();
169 if (isLandingPad()) OS << ", EH LANDING PAD";
172 const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
173 if (!livein_empty()) {
175 for (const_livein_iterator I = livein_begin(),E = livein_end(); I != E; ++I)
176 OutputReg(OS, *I, TRI);
179 // Print the preds of this block according to the CFG.
181 OS << " Predecessors according to CFG:";
182 for (const_pred_iterator PI = pred_begin(), E = pred_end(); PI != E; ++PI)
183 OS << " " << *PI << " (#" << (*PI)->getNumber() << ")";
187 for (const_iterator I = begin(); I != end(); ++I) {
189 I->print(OS, &getParent()->getTarget());
192 // Print the successors of this block according to the CFG.
194 OS << " Successors according to CFG:";
195 for (const_succ_iterator SI = succ_begin(), E = succ_end(); SI != E; ++SI)
196 OS << " " << *SI << " (#" << (*SI)->getNumber() << ")";
201 void MachineBasicBlock::removeLiveIn(unsigned Reg) {
202 livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
203 assert(I != livein_end() && "Not a live in!");
207 void MachineBasicBlock::moveBefore(MachineBasicBlock *NewAfter) {
208 MachineFunction::BasicBlockListType &BBList =getParent()->getBasicBlockList();
209 getParent()->getBasicBlockList().splice(NewAfter, BBList, this);
212 void MachineBasicBlock::moveAfter(MachineBasicBlock *NewBefore) {
213 MachineFunction::BasicBlockListType &BBList =getParent()->getBasicBlockList();
214 MachineFunction::iterator BBI = NewBefore;
215 getParent()->getBasicBlockList().splice(++BBI, BBList, this);
219 void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ) {
220 Successors.push_back(succ);
221 succ->addPredecessor(this);
224 void MachineBasicBlock::removeSuccessor(MachineBasicBlock *succ) {
225 succ->removePredecessor(this);
226 succ_iterator I = std::find(Successors.begin(), Successors.end(), succ);
227 assert(I != Successors.end() && "Not a current successor!");
231 MachineBasicBlock::succ_iterator
232 MachineBasicBlock::removeSuccessor(succ_iterator I) {
233 assert(I != Successors.end() && "Not a current successor!");
234 (*I)->removePredecessor(this);
235 return(Successors.erase(I));
238 void MachineBasicBlock::addPredecessor(MachineBasicBlock *pred) {
239 Predecessors.push_back(pred);
242 void MachineBasicBlock::removePredecessor(MachineBasicBlock *pred) {
243 std::vector<MachineBasicBlock *>::iterator I =
244 std::find(Predecessors.begin(), Predecessors.end(), pred);
245 assert(I != Predecessors.end() && "Pred is not a predecessor of this block!");
246 Predecessors.erase(I);
249 bool MachineBasicBlock::isSuccessor(MachineBasicBlock *MBB) const {
250 std::vector<MachineBasicBlock *>::const_iterator I =
251 std::find(Successors.begin(), Successors.end(), MBB);
252 return I != Successors.end();
255 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
256 /// 'Old', change the code and CFG so that it branches to 'New' instead.
257 void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old,
258 MachineBasicBlock *New) {
259 assert(Old != New && "Cannot replace self with self!");
261 MachineBasicBlock::iterator I = end();
262 while (I != begin()) {
264 if (!I->getDesc().isTerminator()) break;
266 // Scan the operands of this machine instruction, replacing any uses of Old
268 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
269 if (I->getOperand(i).isMBB() && I->getOperand(i).getMBB() == Old)
270 I->getOperand(i).setMBB(New);
273 // Update the successor information. If New was already a successor, just
274 // remove the link to Old instead of creating another one. PR 1444.
275 removeSuccessor(Old);
276 if (!isSuccessor(New))
280 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in the
281 /// CFG to be inserted. If we have proven that MBB can only branch to DestA and
282 /// DestB, remove any other MBB successors from the CFG. DestA and DestB can
284 /// Besides DestA and DestB, retain other edges leading to LandingPads
285 /// (currently there can be only one; we don't check or require that here).
286 /// Note it is possible that DestA and/or DestB are LandingPads.
287 bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA,
288 MachineBasicBlock *DestB,
290 bool MadeChange = false;
291 bool AddedFallThrough = false;
293 MachineBasicBlock *FallThru = getNext();
295 // If this block ends with a conditional branch that falls through to its
296 // successor, set DestB as the successor.
298 if (DestB == 0 && FallThru != getParent()->end()) {
300 AddedFallThrough = true;
303 // If this is an unconditional branch with no explicit dest, it must just be
304 // a fallthrough into DestB.
305 if (DestA == 0 && FallThru != getParent()->end()) {
307 AddedFallThrough = true;
311 MachineBasicBlock::succ_iterator SI = succ_begin();
312 MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
313 while (SI != succ_end()) {
314 if (*SI == DestA && DestA == DestB) {
317 } else if (*SI == DestA) {
320 } else if (*SI == DestB) {
323 } else if ((*SI)->isLandingPad() &&
324 *SI!=OrigDestA && *SI!=OrigDestB) {
327 // Otherwise, this is a superfluous edge, remove it.
328 SI = removeSuccessor(SI);
332 if (!AddedFallThrough) {
333 assert(DestA == 0 && DestB == 0 &&
334 "MachineCFG is missing edges!");
336 assert(DestA == 0 && "MachineCFG is missing edges!");