1 //===- CallGraphSCCPass.cpp - Pass that operates BU on call graph ---------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the CallGraphSCCPass class, which is used for passes
10 // which are implemented as bottom-up traversals on the call graph. Because
11 // there may be cycles in the call graph, passes of this type operate on the
12 // call-graph in SCC order: that is, they process function bottom-up, except for
13 // recursive functions, which they process all at once.
14 //
15 //===----------------------------------------------------------------------===//
16
17 #include "llvm/Analysis/CallGraphSCCPass.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SCCIterator.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/Analysis/CallGraph.h"
22 #include "llvm/IR/AbstractCallSite.h"
23 #include "llvm/IR/Function.h"
24 #include "llvm/IR/IRPrintingPasses.h"
25 #include "llvm/IR/Intrinsics.h"
26 #include "llvm/IR/LLVMContext.h"
27 #include "llvm/IR/LegacyPassManagers.h"
28 #include "llvm/IR/Module.h"
29 #include "llvm/IR/OptBisect.h"
30 #include "llvm/IR/PassTimingInfo.h"
31 #include "llvm/Pass.h"
32 #include "llvm/Support/CommandLine.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/Timer.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include <cassert>
37 #include <string>
38 #include <utility>
39 #include <vector>
40
41 using namespace llvm;
42
43 #define DEBUG_TYPE "cgscc-passmgr"
44
45 static cl::opt<unsigned>
46 MaxIterations("max-cg-scc-iterations", cl::ReallyHidden, cl::init(4));
47
48 STATISTIC(MaxSCCIterations, "Maximum CGSCCPassMgr iterations on one SCC");
49
50 //===----------------------------------------------------------------------===//
51 // CGPassManager
52 //
53 /// CGPassManager manages FPPassManagers and CallGraphSCCPasses.
54
55 namespace {
56
57 class CGPassManager : public ModulePass, public PMDataManager {
58 public:
59 static char ID;
60
CGPassManager()61 explicit CGPassManager() : ModulePass(ID), PMDataManager() {}
62
63 /// Execute all of the passes scheduled for execution. Keep track of
64 /// whether any of the passes modifies the module, and if so, return true.
65 bool runOnModule(Module &M) override;
66
67 using ModulePass::doInitialization;
68 using ModulePass::doFinalization;
69
70 bool doInitialization(CallGraph &CG);
71 bool doFinalization(CallGraph &CG);
72
73 /// Pass Manager itself does not invalidate any analysis info.
getAnalysisUsage(AnalysisUsage & Info) const74 void getAnalysisUsage(AnalysisUsage &Info) const override {
75 // CGPassManager walks SCC and it needs CallGraph.
76 Info.addRequired<CallGraphWrapperPass>();
77 Info.setPreservesAll();
78 }
79
getPassName() const80 StringRef getPassName() const override { return "CallGraph Pass Manager"; }
81
getAsPMDataManager()82 PMDataManager *getAsPMDataManager() override { return this; }
getAsPass()83 Pass *getAsPass() override { return this; }
84
85 // Print passes managed by this manager
dumpPassStructure(unsigned Offset)86 void dumpPassStructure(unsigned Offset) override {
87 errs().indent(Offset*2) << "Call Graph SCC Pass Manager\n";
88 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
89 Pass *P = getContainedPass(Index);
90 P->dumpPassStructure(Offset + 1);
91 dumpLastUses(P, Offset+1);
92 }
93 }
94
getContainedPass(unsigned N)95 Pass *getContainedPass(unsigned N) {
96 assert(N < PassVector.size() && "Pass number out of range!");
97 return static_cast<Pass *>(PassVector[N]);
98 }
99
getPassManagerType() const100 PassManagerType getPassManagerType() const override {
101 return PMT_CallGraphPassManager;
102 }
103
104 private:
105 bool RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG,
106 bool &DevirtualizedCall);
107
108 bool RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC,
109 CallGraph &CG, bool &CallGraphUpToDate,
110 bool &DevirtualizedCall);
111 bool RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
112 bool IsCheckingMode);
113 };
114
115 } // end anonymous namespace.
116
117 char CGPassManager::ID = 0;
118
RunPassOnSCC(Pass * P,CallGraphSCC & CurSCC,CallGraph & CG,bool & CallGraphUpToDate,bool & DevirtualizedCall)119 bool CGPassManager::RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC,
120 CallGraph &CG, bool &CallGraphUpToDate,
121 bool &DevirtualizedCall) {
122 bool Changed = false;
123 PMDataManager *PM = P->getAsPMDataManager();
124 Module &M = CG.getModule();
125
126 if (!PM) {
127 CallGraphSCCPass *CGSP = (CallGraphSCCPass *)P;
128 if (!CallGraphUpToDate) {
129 DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false);
130 CallGraphUpToDate = true;
131 }
132
133 {
134 unsigned InstrCount, SCCCount = 0;
135 StringMap<std::pair<unsigned, unsigned>> FunctionToInstrCount;
136 bool EmitICRemark = M.shouldEmitInstrCountChangedRemark();
137 TimeRegion PassTimer(getPassTimer(CGSP));
138 if (EmitICRemark)
139 InstrCount = initSizeRemarkInfo(M, FunctionToInstrCount);
140 Changed = CGSP->runOnSCC(CurSCC);
141
142 if (EmitICRemark) {
143 // FIXME: Add getInstructionCount to CallGraphSCC.
144 SCCCount = M.getInstructionCount();
145 // Is there a difference in the number of instructions in the module?
146 if (SCCCount != InstrCount) {
147 // Yep. Emit a remark and update InstrCount.
148 int64_t Delta =
149 static_cast<int64_t>(SCCCount) - static_cast<int64_t>(InstrCount);
150 emitInstrCountChangedRemark(P, M, Delta, InstrCount,
151 FunctionToInstrCount);
152 InstrCount = SCCCount;
153 }
154 }
155 }
156
157 // After the CGSCCPass is done, when assertions are enabled, use
158 // RefreshCallGraph to verify that the callgraph was correctly updated.
159 #ifndef NDEBUG
160 if (Changed)
161 RefreshCallGraph(CurSCC, CG, true);
162 #endif
163
164 return Changed;
165 }
166
167 assert(PM->getPassManagerType() == PMT_FunctionPassManager &&
168 "Invalid CGPassManager member");
169 FPPassManager *FPP = (FPPassManager*)P;
170
171 // Run pass P on all functions in the current SCC.
172 for (CallGraphNode *CGN : CurSCC) {
173 if (Function *F = CGN->getFunction()) {
174 dumpPassInfo(P, EXECUTION_MSG, ON_FUNCTION_MSG, F->getName());
175 {
176 TimeRegion PassTimer(getPassTimer(FPP));
177 Changed |= FPP->runOnFunction(*F);
178 }
179 F->getContext().yield();
180 }
181 }
182
183 // The function pass(es) modified the IR, they may have clobbered the
184 // callgraph.
185 if (Changed && CallGraphUpToDate) {
186 LLVM_DEBUG(dbgs() << "CGSCCPASSMGR: Pass Dirtied SCC: " << P->getPassName()
187 << '\n');
188 CallGraphUpToDate = false;
189 }
190 return Changed;
191 }
192
193 /// Scan the functions in the specified CFG and resync the
194 /// callgraph with the call sites found in it. This is used after
195 /// FunctionPasses have potentially munged the callgraph, and can be used after
196 /// CallGraphSCC passes to verify that they correctly updated the callgraph.
197 ///
198 /// This function returns true if it devirtualized an existing function call,
199 /// meaning it turned an indirect call into a direct call. This happens when
200 /// a function pass like GVN optimizes away stuff feeding the indirect call.
201 /// This never happens in checking mode.
RefreshCallGraph(const CallGraphSCC & CurSCC,CallGraph & CG,bool CheckingMode)202 bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
203 bool CheckingMode) {
204 DenseMap<Value *, CallGraphNode *> Calls;
205
206 LLVM_DEBUG(dbgs() << "CGSCCPASSMGR: Refreshing SCC with " << CurSCC.size()
207 << " nodes:\n";
208 for (CallGraphNode *CGN
209 : CurSCC) CGN->dump(););
210
211 bool MadeChange = false;
212 bool DevirtualizedCall = false;
213
214 // Scan all functions in the SCC.
215 unsigned FunctionNo = 0;
216 for (CallGraphSCC::iterator SCCIdx = CurSCC.begin(), E = CurSCC.end();
217 SCCIdx != E; ++SCCIdx, ++FunctionNo) {
218 CallGraphNode *CGN = *SCCIdx;
219 Function *F = CGN->getFunction();
220 if (!F || F->isDeclaration()) continue;
221
222 // Walk the function body looking for call sites. Sync up the call sites in
223 // CGN with those actually in the function.
224
225 // Keep track of the number of direct and indirect calls that were
226 // invalidated and removed.
227 unsigned NumDirectRemoved = 0, NumIndirectRemoved = 0;
228
229 CallGraphNode::iterator CGNEnd = CGN->end();
230
231 auto RemoveAndCheckForDone = [&](CallGraphNode::iterator I) {
232 // Just remove the edge from the set of callees, keep track of whether
233 // I points to the last element of the vector.
234 bool WasLast = I + 1 == CGNEnd;
235 CGN->removeCallEdge(I);
236
237 // If I pointed to the last element of the vector, we have to bail out:
238 // iterator checking rejects comparisons of the resultant pointer with
239 // end.
240 if (WasLast)
241 return true;
242
243 CGNEnd = CGN->end();
244 return false;
245 };
246
247 // Get the set of call sites currently in the function.
248 for (CallGraphNode::iterator I = CGN->begin(); I != CGNEnd;) {
249 // Delete "reference" call records that do not have call instruction. We
250 // reinsert them as needed later. However, keep them in checking mode.
251 if (!I->first) {
252 if (CheckingMode) {
253 ++I;
254 continue;
255 }
256 if (RemoveAndCheckForDone(I))
257 break;
258 continue;
259 }
260
261 // If this call site is null, then the function pass deleted the call
262 // entirely and the WeakTrackingVH nulled it out.
263 auto *Call = dyn_cast_or_null<CallBase>(*I->first);
264 if (!Call ||
265 // If we've already seen this call site, then the FunctionPass RAUW'd
266 // one call with another, which resulted in two "uses" in the edge
267 // list of the same call.
268 Calls.count(Call) ||
269
270 // If the call edge is not from a call or invoke, or it is a
271 // instrinsic call, then the function pass RAUW'd a call with
272 // another value. This can happen when constant folding happens
273 // of well known functions etc.
274 (Call->getCalledFunction() &&
275 Call->getCalledFunction()->isIntrinsic() &&
276 Intrinsic::isLeaf(Call->getCalledFunction()->getIntrinsicID()))) {
277 assert(!CheckingMode &&
278 "CallGraphSCCPass did not update the CallGraph correctly!");
279
280 // If this was an indirect call site, count it.
281 if (!I->second->getFunction())
282 ++NumIndirectRemoved;
283 else
284 ++NumDirectRemoved;
285
286 if (RemoveAndCheckForDone(I))
287 break;
288 continue;
289 }
290
291 assert(!Calls.count(Call) && "Call site occurs in node multiple times");
292
293 if (Call) {
294 Function *Callee = Call->getCalledFunction();
295 // Ignore intrinsics because they're not really function calls.
296 if (!Callee || !(Callee->isIntrinsic()))
297 Calls.insert(std::make_pair(Call, I->second));
298 }
299 ++I;
300 }
301
302 // Loop over all of the instructions in the function, getting the callsites.
303 // Keep track of the number of direct/indirect calls added.
304 unsigned NumDirectAdded = 0, NumIndirectAdded = 0;
305
306 for (BasicBlock &BB : *F)
307 for (Instruction &I : BB) {
308 auto *Call = dyn_cast<CallBase>(&I);
309 if (!Call)
310 continue;
311 Function *Callee = Call->getCalledFunction();
312 if (Callee && Callee->isIntrinsic())
313 continue;
314
315 // If we are not in checking mode, insert potential callback calls as
316 // references. This is not a requirement but helps to iterate over the
317 // functions in the right order.
318 if (!CheckingMode) {
319 forEachCallbackFunction(*Call, [&](Function *CB) {
320 CGN->addCalledFunction(nullptr, CG.getOrInsertFunction(CB));
321 });
322 }
323
324 // If this call site already existed in the callgraph, just verify it
325 // matches up to expectations and remove it from Calls.
326 DenseMap<Value *, CallGraphNode *>::iterator ExistingIt =
327 Calls.find(Call);
328 if (ExistingIt != Calls.end()) {
329 CallGraphNode *ExistingNode = ExistingIt->second;
330
331 // Remove from Calls since we have now seen it.
332 Calls.erase(ExistingIt);
333
334 // Verify that the callee is right.
335 if (ExistingNode->getFunction() == Call->getCalledFunction())
336 continue;
337
338 // If we are in checking mode, we are not allowed to actually mutate
339 // the callgraph. If this is a case where we can infer that the
340 // callgraph is less precise than it could be (e.g. an indirect call
341 // site could be turned direct), don't reject it in checking mode, and
342 // don't tweak it to be more precise.
343 if (CheckingMode && Call->getCalledFunction() &&
344 ExistingNode->getFunction() == nullptr)
345 continue;
346
347 assert(!CheckingMode &&
348 "CallGraphSCCPass did not update the CallGraph correctly!");
349
350 // If not, we either went from a direct call to indirect, indirect to
351 // direct, or direct to different direct.
352 CallGraphNode *CalleeNode;
353 if (Function *Callee = Call->getCalledFunction()) {
354 CalleeNode = CG.getOrInsertFunction(Callee);
355 // Keep track of whether we turned an indirect call into a direct
356 // one.
357 if (!ExistingNode->getFunction()) {
358 DevirtualizedCall = true;
359 LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Devirtualized call to '"
360 << Callee->getName() << "'\n");
361 }
362 } else {
363 CalleeNode = CG.getCallsExternalNode();
364 }
365
366 // Update the edge target in CGN.
367 CGN->replaceCallEdge(*Call, *Call, CalleeNode);
368 MadeChange = true;
369 continue;
370 }
371
372 assert(!CheckingMode &&
373 "CallGraphSCCPass did not update the CallGraph correctly!");
374
375 // If the call site didn't exist in the CGN yet, add it.
376 CallGraphNode *CalleeNode;
377 if (Function *Callee = Call->getCalledFunction()) {
378 CalleeNode = CG.getOrInsertFunction(Callee);
379 ++NumDirectAdded;
380 } else {
381 CalleeNode = CG.getCallsExternalNode();
382 ++NumIndirectAdded;
383 }
384
385 CGN->addCalledFunction(Call, CalleeNode);
386 MadeChange = true;
387 }
388
389 // We scanned the old callgraph node, removing invalidated call sites and
390 // then added back newly found call sites. One thing that can happen is
391 // that an old indirect call site was deleted and replaced with a new direct
392 // call. In this case, we have devirtualized a call, and CGSCCPM would like
393 // to iteratively optimize the new code. Unfortunately, we don't really
394 // have a great way to detect when this happens. As an approximation, we
395 // just look at whether the number of indirect calls is reduced and the
396 // number of direct calls is increased. There are tons of ways to fool this
397 // (e.g. DCE'ing an indirect call and duplicating an unrelated block with a
398 // direct call) but this is close enough.
399 if (NumIndirectRemoved > NumIndirectAdded &&
400 NumDirectRemoved < NumDirectAdded)
401 DevirtualizedCall = true;
402
403 // After scanning this function, if we still have entries in callsites, then
404 // they are dangling pointers. WeakTrackingVH should save us for this, so
405 // abort if
406 // this happens.
407 assert(Calls.empty() && "Dangling pointers found in call sites map");
408
409 // Periodically do an explicit clear to remove tombstones when processing
410 // large scc's.
411 if ((FunctionNo & 15) == 15)
412 Calls.clear();
413 }
414
415 LLVM_DEBUG(if (MadeChange) {
416 dbgs() << "CGSCCPASSMGR: Refreshed SCC is now:\n";
417 for (CallGraphNode *CGN : CurSCC)
418 CGN->dump();
419 if (DevirtualizedCall)
420 dbgs() << "CGSCCPASSMGR: Refresh devirtualized a call!\n";
421 } else {
422 dbgs() << "CGSCCPASSMGR: SCC Refresh didn't change call graph.\n";
423 });
424 (void)MadeChange;
425
426 return DevirtualizedCall;
427 }
428
429 /// Execute the body of the entire pass manager on the specified SCC.
430 /// This keeps track of whether a function pass devirtualizes
431 /// any calls and returns it in DevirtualizedCall.
RunAllPassesOnSCC(CallGraphSCC & CurSCC,CallGraph & CG,bool & DevirtualizedCall)432 bool CGPassManager::RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG,
433 bool &DevirtualizedCall) {
434 bool Changed = false;
435
436 // Keep track of whether the callgraph is known to be up-to-date or not.
437 // The CGSSC pass manager runs two types of passes:
438 // CallGraphSCC Passes and other random function passes. Because other
439 // random function passes are not CallGraph aware, they may clobber the
440 // call graph by introducing new calls or deleting other ones. This flag
441 // is set to false when we run a function pass so that we know to clean up
442 // the callgraph when we need to run a CGSCCPass again.
443 bool CallGraphUpToDate = true;
444
445 // Run all passes on current SCC.
446 for (unsigned PassNo = 0, e = getNumContainedPasses();
447 PassNo != e; ++PassNo) {
448 Pass *P = getContainedPass(PassNo);
449
450 // If we're in -debug-pass=Executions mode, construct the SCC node list,
451 // otherwise avoid constructing this string as it is expensive.
452 if (isPassDebuggingExecutionsOrMore()) {
453 std::string Functions;
454 #ifndef NDEBUG
455 raw_string_ostream OS(Functions);
456 for (CallGraphSCC::iterator I = CurSCC.begin(), E = CurSCC.end();
457 I != E; ++I) {
458 if (I != CurSCC.begin()) OS << ", ";
459 (*I)->print(OS);
460 }
461 OS.flush();
462 #endif
463 dumpPassInfo(P, EXECUTION_MSG, ON_CG_MSG, Functions);
464 }
465 dumpRequiredSet(P);
466
467 initializeAnalysisImpl(P);
468
469 // Actually run this pass on the current SCC.
470 Changed |= RunPassOnSCC(P, CurSCC, CG,
471 CallGraphUpToDate, DevirtualizedCall);
472
473 if (Changed)
474 dumpPassInfo(P, MODIFICATION_MSG, ON_CG_MSG, "");
475 dumpPreservedSet(P);
476
477 verifyPreservedAnalysis(P);
478 removeNotPreservedAnalysis(P);
479 recordAvailableAnalysis(P);
480 removeDeadPasses(P, "", ON_CG_MSG);
481 }
482
483 // If the callgraph was left out of date (because the last pass run was a
484 // functionpass), refresh it before we move on to the next SCC.
485 if (!CallGraphUpToDate)
486 DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, false);
487 return Changed;
488 }
489
490 /// Execute all of the passes scheduled for execution. Keep track of
491 /// whether any of the passes modifies the module, and if so, return true.
runOnModule(Module & M)492 bool CGPassManager::runOnModule(Module &M) {
493 CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
494 bool Changed = doInitialization(CG);
495
496 // Walk the callgraph in bottom-up SCC order.
497 scc_iterator<CallGraph*> CGI = scc_begin(&CG);
498
499 CallGraphSCC CurSCC(CG, &CGI);
500 while (!CGI.isAtEnd()) {
501 // Copy the current SCC and increment past it so that the pass can hack
502 // on the SCC if it wants to without invalidating our iterator.
503 const std::vector<CallGraphNode *> &NodeVec = *CGI;
504 CurSCC.initialize(NodeVec);
505 ++CGI;
506
507 // At the top level, we run all the passes in this pass manager on the
508 // functions in this SCC. However, we support iterative compilation in the
509 // case where a function pass devirtualizes a call to a function. For
510 // example, it is very common for a function pass (often GVN or instcombine)
511 // to eliminate the addressing that feeds into a call. With that improved
512 // information, we would like the call to be an inline candidate, infer
513 // mod-ref information etc.
514 //
515 // Because of this, we allow iteration up to a specified iteration count.
516 // This only happens in the case of a devirtualized call, so we only burn
517 // compile time in the case that we're making progress. We also have a hard
518 // iteration count limit in case there is crazy code.
519 unsigned Iteration = 0;
520 bool DevirtualizedCall = false;
521 do {
522 LLVM_DEBUG(if (Iteration) dbgs()
523 << " SCCPASSMGR: Re-visiting SCC, iteration #" << Iteration
524 << '\n');
525 DevirtualizedCall = false;
526 Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall);
527 } while (Iteration++ < MaxIterations && DevirtualizedCall);
528
529 if (DevirtualizedCall)
530 LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after "
531 << Iteration
532 << " times, due to -max-cg-scc-iterations\n");
533
534 MaxSCCIterations.updateMax(Iteration);
535 }
536 Changed |= doFinalization(CG);
537 return Changed;
538 }
539
540 /// Initialize CG
doInitialization(CallGraph & CG)541 bool CGPassManager::doInitialization(CallGraph &CG) {
542 bool Changed = false;
543 for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) {
544 if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) {
545 assert(PM->getPassManagerType() == PMT_FunctionPassManager &&
546 "Invalid CGPassManager member");
547 Changed |= ((FPPassManager*)PM)->doInitialization(CG.getModule());
548 } else {
549 Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doInitialization(CG);
550 }
551 }
552 return Changed;
553 }
554
555 /// Finalize CG
doFinalization(CallGraph & CG)556 bool CGPassManager::doFinalization(CallGraph &CG) {
557 bool Changed = false;
558 for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) {
559 if (PMDataManager *PM = getContainedPass(i)->getAsPMDataManager()) {
560 assert(PM->getPassManagerType() == PMT_FunctionPassManager &&
561 "Invalid CGPassManager member");
562 Changed |= ((FPPassManager*)PM)->doFinalization(CG.getModule());
563 } else {
564 Changed |= ((CallGraphSCCPass*)getContainedPass(i))->doFinalization(CG);
565 }
566 }
567 return Changed;
568 }
569
570 //===----------------------------------------------------------------------===//
571 // CallGraphSCC Implementation
572 //===----------------------------------------------------------------------===//
573
574 /// This informs the SCC and the pass manager that the specified
575 /// Old node has been deleted, and New is to be used in its place.
ReplaceNode(CallGraphNode * Old,CallGraphNode * New)576 void CallGraphSCC::ReplaceNode(CallGraphNode *Old, CallGraphNode *New) {
577 assert(Old != New && "Should not replace node with self");
578 for (unsigned i = 0; ; ++i) {
579 assert(i != Nodes.size() && "Node not in SCC");
580 if (Nodes[i] != Old) continue;
581 if (New)
582 Nodes[i] = New;
583 else
584 Nodes.erase(Nodes.begin() + i);
585 break;
586 }
587
588 // Update the active scc_iterator so that it doesn't contain dangling
589 // pointers to the old CallGraphNode.
590 scc_iterator<CallGraph*> *CGI = (scc_iterator<CallGraph*>*)Context;
591 CGI->ReplaceNode(Old, New);
592 }
593
DeleteNode(CallGraphNode * Old)594 void CallGraphSCC::DeleteNode(CallGraphNode *Old) {
595 ReplaceNode(Old, /*New=*/nullptr);
596 }
597
598 //===----------------------------------------------------------------------===//
599 // CallGraphSCCPass Implementation
600 //===----------------------------------------------------------------------===//
601
602 /// Assign pass manager to manage this pass.
assignPassManager(PMStack & PMS,PassManagerType PreferredType)603 void CallGraphSCCPass::assignPassManager(PMStack &PMS,
604 PassManagerType PreferredType) {
605 // Find CGPassManager
606 while (!PMS.empty() &&
607 PMS.top()->getPassManagerType() > PMT_CallGraphPassManager)
608 PMS.pop();
609
610 assert(!PMS.empty() && "Unable to handle Call Graph Pass");
611 CGPassManager *CGP;
612
613 if (PMS.top()->getPassManagerType() == PMT_CallGraphPassManager)
614 CGP = (CGPassManager*)PMS.top();
615 else {
616 // Create new Call Graph SCC Pass Manager if it does not exist.
617 assert(!PMS.empty() && "Unable to create Call Graph Pass Manager");
618 PMDataManager *PMD = PMS.top();
619
620 // [1] Create new Call Graph Pass Manager
621 CGP = new CGPassManager();
622
623 // [2] Set up new manager's top level manager
624 PMTopLevelManager *TPM = PMD->getTopLevelManager();
625 TPM->addIndirectPassManager(CGP);
626
627 // [3] Assign manager to manage this new manager. This may create
628 // and push new managers into PMS
629 Pass *P = CGP;
630 TPM->schedulePass(P);
631
632 // [4] Push new manager into PMS
633 PMS.push(CGP);
634 }
635
636 CGP->add(this);
637 }
638
639 /// For this class, we declare that we require and preserve the call graph.
640 /// If the derived class implements this method, it should
641 /// always explicitly call the implementation here.
getAnalysisUsage(AnalysisUsage & AU) const642 void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const {
643 AU.addRequired<CallGraphWrapperPass>();
644 AU.addPreserved<CallGraphWrapperPass>();
645 }
646
647 //===----------------------------------------------------------------------===//
648 // PrintCallGraphPass Implementation
649 //===----------------------------------------------------------------------===//
650
651 namespace {
652
653 /// PrintCallGraphPass - Print a Module corresponding to a call graph.
654 ///
655 class PrintCallGraphPass : public CallGraphSCCPass {
656 std::string Banner;
657 raw_ostream &OS; // raw_ostream to print on.
658
659 public:
660 static char ID;
661
PrintCallGraphPass(const std::string & B,raw_ostream & OS)662 PrintCallGraphPass(const std::string &B, raw_ostream &OS)
663 : CallGraphSCCPass(ID), Banner(B), OS(OS) {}
664
getAnalysisUsage(AnalysisUsage & AU) const665 void getAnalysisUsage(AnalysisUsage &AU) const override {
666 AU.setPreservesAll();
667 }
668
runOnSCC(CallGraphSCC & SCC)669 bool runOnSCC(CallGraphSCC &SCC) override {
670 bool BannerPrinted = false;
671 auto PrintBannerOnce = [&]() {
672 if (BannerPrinted)
673 return;
674 OS << Banner;
675 BannerPrinted = true;
676 };
677
678 bool NeedModule = llvm::forcePrintModuleIR();
679 if (isFunctionInPrintList("*") && NeedModule) {
680 PrintBannerOnce();
681 OS << "\n";
682 SCC.getCallGraph().getModule().print(OS, nullptr);
683 return false;
684 }
685 bool FoundFunction = false;
686 for (CallGraphNode *CGN : SCC) {
687 if (Function *F = CGN->getFunction()) {
688 if (!F->isDeclaration() && isFunctionInPrintList(F->getName())) {
689 FoundFunction = true;
690 if (!NeedModule) {
691 PrintBannerOnce();
692 F->print(OS);
693 }
694 }
695 } else if (isFunctionInPrintList("*")) {
696 PrintBannerOnce();
697 OS << "\nPrinting <null> Function\n";
698 }
699 }
700 if (NeedModule && FoundFunction) {
701 PrintBannerOnce();
702 OS << "\n";
703 SCC.getCallGraph().getModule().print(OS, nullptr);
704 }
705 return false;
706 }
707
getPassName() const708 StringRef getPassName() const override { return "Print CallGraph IR"; }
709 };
710
711 } // end anonymous namespace.
712
713 char PrintCallGraphPass::ID = 0;
714
createPrinterPass(raw_ostream & OS,const std::string & Banner) const715 Pass *CallGraphSCCPass::createPrinterPass(raw_ostream &OS,
716 const std::string &Banner) const {
717 return new PrintCallGraphPass(Banner, OS);
718 }
719
getDescription(const CallGraphSCC & SCC)720 static std::string getDescription(const CallGraphSCC &SCC) {
721 std::string Desc = "SCC (";
722 bool First = true;
723 for (CallGraphNode *CGN : SCC) {
724 if (First)
725 First = false;
726 else
727 Desc += ", ";
728 Function *F = CGN->getFunction();
729 if (F)
730 Desc += F->getName();
731 else
732 Desc += "<<null function>>";
733 }
734 Desc += ")";
735 return Desc;
736 }
737
skipSCC(CallGraphSCC & SCC) const738 bool CallGraphSCCPass::skipSCC(CallGraphSCC &SCC) const {
739 OptPassGate &Gate =
740 SCC.getCallGraph().getModule().getContext().getOptPassGate();
741 return Gate.isEnabled() && !Gate.shouldRunPass(this, getDescription(SCC));
742 }
743
744 char DummyCGSCCPass::ID = 0;
745
746 INITIALIZE_PASS(DummyCGSCCPass, "DummyCGSCCPass", "DummyCGSCCPass", false,
747 false)
748