1 //===- LoopPass.cpp - Loop Pass and Loop Pass Manager ---------------------===//
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 // This file implements LoopPass and LPPassManager. All loop optimization
11 // and transformation passes are derived from LoopPass. LPPassManager is
12 // responsible for managing LoopPasses.
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Analysis/LoopPass.h"
19 //===----------------------------------------------------------------------===//
23 char LPPassManager::ID = 0;
25 LPPassManager::LPPassManager(int Depth)
26 : FunctionPass(&ID), PMDataManager(Depth) {
33 /// Delete loop from the loop queue and loop hierarchy (LoopInfo).
34 void LPPassManager::deleteLoopFromQueue(Loop *L) {
36 if (Loop *ParentLoop = L->getParentLoop()) { // Not a top-level loop.
37 // Reparent all of the blocks in this loop. Since BBLoop had a parent,
38 // they are now all in it.
39 for (Loop::block_iterator I = L->block_begin(), E = L->block_end();
41 if (LI->getLoopFor(*I) == L) // Don't change blocks in subloops.
42 LI->changeLoopFor(*I, ParentLoop);
44 // Remove the loop from its parent loop.
45 for (Loop::iterator I = ParentLoop->begin(), E = ParentLoop->end();;
47 assert(I != E && "Couldn't find loop");
49 ParentLoop->removeChildLoop(I);
54 // Move all subloops into the parent loop.
56 ParentLoop->addChildLoop(L->removeChildLoop(L->end()-1));
58 // Reparent all of the blocks in this loop. Since BBLoop had no parent,
59 // they no longer in a loop at all.
61 for (unsigned i = 0; i != L->getBlocks().size(); ++i) {
62 // Don't change blocks in subloops.
63 if (LI->getLoopFor(L->getBlocks()[i]) == L) {
64 LI->removeBlock(L->getBlocks()[i]);
69 // Remove the loop from the top-level LoopInfo object.
70 for (LoopInfo::iterator I = LI->begin(), E = LI->end();; ++I) {
71 assert(I != E && "Couldn't find loop");
78 // Move all of the subloops to the top-level.
80 LI->addTopLevelLoop(L->removeChildLoop(L->end()-1));
85 // If L is current loop then skip rest of the passes and let
86 // runOnFunction remove L from LQ. Otherwise, remove L from LQ now
87 // and continue applying other passes on CurrentLoop.
88 if (CurrentLoop == L) {
93 for (std::deque<Loop *>::iterator I = LQ.begin(),
94 E = LQ.end(); I != E; ++I) {
102 // Inset loop into loop nest (LoopInfo) and loop queue (LQ).
103 void LPPassManager::insertLoop(Loop *L, Loop *ParentLoop) {
105 assert (CurrentLoop != L && "Cannot insert CurrentLoop");
107 // Insert into loop nest
109 ParentLoop->addChildLoop(L);
111 LI->addTopLevelLoop(L);
113 insertLoopIntoQueue(L);
116 void LPPassManager::insertLoopIntoQueue(Loop *L) {
117 // Insert L into loop queue
118 if (L == CurrentLoop)
120 else if (!L->getParentLoop())
121 // This is top level loop.
124 // Insert L after the parent loop.
125 for (std::deque<Loop *>::iterator I = LQ.begin(),
126 E = LQ.end(); I != E; ++I) {
127 if (*I == L->getParentLoop()) {
128 // deque does not support insert after.
137 // Reoptimize this loop. LPPassManager will re-insert this loop into the
138 // queue. This allows LoopPass to change loop nest for the loop. This
139 // utility may send LPPassManager into infinite loops so use caution.
140 void LPPassManager::redoLoop(Loop *L) {
141 assert (CurrentLoop == L && "Can redo only CurrentLoop");
145 /// cloneBasicBlockSimpleAnalysis - Invoke cloneBasicBlockAnalysis hook for
147 void LPPassManager::cloneBasicBlockSimpleAnalysis(BasicBlock *From,
148 BasicBlock *To, Loop *L) {
149 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
150 Pass *P = getContainedPass(Index);
151 LoopPass *LP = dynamic_cast<LoopPass *>(P);
152 LP->cloneBasicBlockAnalysis(From, To, L);
156 /// deleteSimpleAnalysisValue - Invoke deleteAnalysisValue hook for all passes.
157 void LPPassManager::deleteSimpleAnalysisValue(Value *V, Loop *L) {
158 if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
159 for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;
161 Instruction &I = *BI;
162 deleteSimpleAnalysisValue(&I, L);
165 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
166 Pass *P = getContainedPass(Index);
167 LoopPass *LP = dynamic_cast<LoopPass *>(P);
168 LP->deleteAnalysisValue(V, L);
173 // Recurse through all subloops and all loops into LQ.
174 static void addLoopIntoQueue(Loop *L, std::deque<Loop *> &LQ) {
176 for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
177 addLoopIntoQueue(*I, LQ);
180 /// Pass Manager itself does not invalidate any analysis info.
181 void LPPassManager::getAnalysisUsage(AnalysisUsage &Info) const {
182 // LPPassManager needs LoopInfo. In the long term LoopInfo class will
183 // become part of LPPassManager.
184 Info.addRequired<LoopInfo>();
185 Info.setPreservesAll();
188 /// run - Execute all of the passes scheduled for execution. Keep track of
189 /// whether any of the passes modifies the function, and if so, return true.
190 bool LPPassManager::runOnFunction(Function &F) {
191 LI = &getAnalysis<LoopInfo>();
192 bool Changed = false;
194 // Collect inherited analysis from Module level pass manager.
195 populateInheritedAnalysis(TPM->activeStack);
197 // Populate Loop Queue
198 for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
199 addLoopIntoQueue(*I, LQ);
201 if (LQ.empty()) // No loops, skip calling finalizers
205 for (std::deque<Loop *>::const_iterator I = LQ.begin(), E = LQ.end();
208 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
209 Pass *P = getContainedPass(Index);
210 LoopPass *LP = dynamic_cast<LoopPass *>(P);
212 Changed |= LP->doInitialization(L, *this);
217 while (!LQ.empty()) {
219 CurrentLoop = LQ.back();
220 skipThisLoop = false;
221 redoThisLoop = false;
223 // Run all passes on the current Loop.
224 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
225 Pass *P = getContainedPass(Index);
227 dumpPassInfo(P, EXECUTION_MSG, ON_LOOP_MSG, "");
230 initializeAnalysisImpl(P);
232 LoopPass *LP = dynamic_cast<LoopPass *>(P);
234 PassManagerPrettyStackEntry X(LP, *CurrentLoop->getHeader());
235 assert(LP && "Invalid LPPassManager member");
236 Timer *T = StartPassTimer(P);
237 Changed |= LP->runOnLoop(CurrentLoop, *this);
242 dumpPassInfo(P, MODIFICATION_MSG, ON_LOOP_MSG, "");
246 verifyPreservedAnalysis(LP);
248 removeNotPreservedAnalysis(P);
249 recordAvailableAnalysis(P);
250 removeDeadPasses(P, "", ON_LOOP_MSG);
252 // If dominator information is available then verify the info if requested.
253 verifyDomInfo(*LP, F);
256 // Do not run other passes on this loop.
260 // If the loop was deleted, release all the loop passes. This frees up
261 // some memory, and avoids trouble with the pass manager trying to call
262 // verifyAnalysis on them.
264 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
265 Pass *P = getContainedPass(Index);
266 freePass(P, "", ON_LOOP_MSG);
269 // Pop the loop from queue after running all passes.
273 LQ.push_back(CurrentLoop);
277 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
278 Pass *P = getContainedPass(Index);
279 LoopPass *LP = dynamic_cast <LoopPass *>(P);
281 Changed |= LP->doFinalization();
287 /// Print passes managed by this manager
288 void LPPassManager::dumpPassStructure(unsigned Offset) {
289 errs().indent(Offset*2) << "Loop Pass Manager\n";
290 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
291 Pass *P = getContainedPass(Index);
292 P->dumpPassStructure(Offset + 1);
293 dumpLastUses(P, Offset+1);
298 //===----------------------------------------------------------------------===//
301 // Check if this pass is suitable for the current LPPassManager, if
302 // available. This pass P is not suitable for a LPPassManager if P
303 // is not preserving higher level analysis info used by other
304 // LPPassManager passes. In such case, pop LPPassManager from the
305 // stack. This will force assignPassManager() to create new
306 // LPPassManger as expected.
307 void LoopPass::preparePassManager(PMStack &PMS) {
309 // Find LPPassManager
310 while (!PMS.empty() &&
311 PMS.top()->getPassManagerType() > PMT_LoopPassManager)
314 LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
316 // If this pass is destroying high level information that is used
317 // by other passes that are managed by LPM then do not insert
318 // this pass in current LPM. Use new LPPassManager.
319 if (LPPM && !LPPM->preserveHigherLevelAnalysis(this))
323 /// Assign pass manager to manage this pass.
324 void LoopPass::assignPassManager(PMStack &PMS,
325 PassManagerType PreferredType) {
326 // Find LPPassManager
327 while (!PMS.empty() &&
328 PMS.top()->getPassManagerType() > PMT_LoopPassManager)
331 LPPassManager *LPPM = dynamic_cast<LPPassManager *>(PMS.top());
333 // Create new Loop Pass Manager if it does not exist.
336 assert (!PMS.empty() && "Unable to create Loop Pass Manager");
337 PMDataManager *PMD = PMS.top();
339 // [1] Create new Call Graph Pass Manager
340 LPPM = new LPPassManager(PMD->getDepth() + 1);
341 LPPM->populateInheritedAnalysis(PMS);
343 // [2] Set up new manager's top level manager
344 PMTopLevelManager *TPM = PMD->getTopLevelManager();
345 TPM->addIndirectPassManager(LPPM);
347 // [3] Assign manager to manage this new manager. This may create
348 // and push new managers into PMS
349 Pass *P = dynamic_cast<Pass *>(LPPM);
350 TPM->schedulePass(P);
352 // [4] Push new manager into PMS