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/ADT/StringExtras.h"
22#include "llvm/Analysis/CallGraph.h"
23#include "llvm/IR/AbstractCallSite.h"
24#include "llvm/IR/Function.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/PassTimingInfo.h"
30#include "llvm/IR/PrintPasses.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
41using namespace llvm;
42
43#define DEBUG_TYPE "cgscc-passmgr"
44
45namespace llvm {
46cl::opt<unsigned> MaxDevirtIterations("max-devirt-iterations", cl::ReallyHidden,
47 cl::init(Val: 4));
48} // namespace llvm
49
50STATISTIC(MaxSCCIterations, "Maximum CGSCCPassMgr iterations on one SCC");
51
52//===----------------------------------------------------------------------===//
53// CGPassManager
54//
55/// CGPassManager manages FPPassManagers and CallGraphSCCPasses.
56
57namespace {
58
59class CGPassManager : public ModulePass, public PMDataManager {
60public:
61 static char ID;
62
63 explicit CGPassManager() : ModulePass(ID) {}
64
65 /// Execute all of the passes scheduled for execution. Keep track of
66 /// whether any of the passes modifies the module, and if so, return true.
67 bool runOnModule(Module &M) override;
68
69 using ModulePass::doInitialization;
70 using ModulePass::doFinalization;
71
72 bool doInitialization(CallGraph &CG);
73 bool doFinalization(CallGraph &CG);
74
75 /// Pass Manager itself does not invalidate any analysis info.
76 void getAnalysisUsage(AnalysisUsage &Info) const override {
77 // CGPassManager walks SCC and it needs CallGraph.
78 Info.addRequired<CallGraphWrapperPass>();
79 Info.setPreservesAll();
80 }
81
82 StringRef getPassName() const override { return "CallGraph Pass Manager"; }
83
84 PMDataManager *getAsPMDataManager() override { return this; }
85 Pass *getAsPass() override { return this; }
86
87 // Print passes managed by this manager
88 void dumpPassStructure(unsigned Offset) override {
89 errs().indent(NumSpaces: Offset*2) << "Call Graph SCC Pass Manager\n";
90 for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
91 Pass *P = getContainedPass(N: Index);
92 P->dumpPassStructure(Offset: Offset + 1);
93 dumpLastUses(P, Offset: Offset+1);
94 }
95 }
96
97 Pass *getContainedPass(unsigned N) {
98 assert(N < PassVector.size() && "Pass number out of range!");
99 return static_cast<Pass *>(PassVector[N]);
100 }
101
102 PassManagerType getPassManagerType() const override {
103 return PMT_CallGraphPassManager;
104 }
105
106private:
107 bool RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG,
108 bool &DevirtualizedCall);
109
110 bool RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC,
111 CallGraph &CG, bool &CallGraphUpToDate,
112 bool &DevirtualizedCall);
113 bool RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
114 bool IsCheckingMode);
115};
116
117} // end anonymous namespace.
118
119char CGPassManager::ID = 0;
120
121bool CGPassManager::RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC,
122 CallGraph &CG, bool &CallGraphUpToDate,
123 bool &DevirtualizedCall) {
124 bool Changed = false;
125 PMDataManager *PM = P->getAsPMDataManager();
126 Module &M = CG.getModule();
127
128 if (!PM) {
129 CallGraphSCCPass *CGSP = (CallGraphSCCPass *)P;
130 if (!CallGraphUpToDate) {
131 DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, IsCheckingMode: false);
132 CallGraphUpToDate = true;
133 }
134
135 {
136 unsigned InstrCount, SCCCount = 0;
137 StringMap<std::pair<unsigned, unsigned>> FunctionToInstrCount;
138 bool EmitICRemark = M.shouldEmitInstrCountChangedRemark();
139 TimeRegion PassTimer(getPassTimer(CGSP));
140 if (EmitICRemark)
141 InstrCount = initSizeRemarkInfo(M, FunctionToInstrCount);
142 Changed = CGSP->runOnSCC(SCC&: CurSCC);
143
144 if (EmitICRemark) {
145 // FIXME: Add getInstructionCount to CallGraphSCC.
146 SCCCount = M.getInstructionCount();
147 // Is there a difference in the number of instructions in the module?
148 if (SCCCount != InstrCount) {
149 // Yep. Emit a remark and update InstrCount.
150 int64_t Delta =
151 static_cast<int64_t>(SCCCount) - static_cast<int64_t>(InstrCount);
152 emitInstrCountChangedRemark(P, M, Delta, CountBefore: InstrCount,
153 FunctionToInstrCount);
154 InstrCount = SCCCount;
155 }
156 }
157 }
158
159 // After the CGSCCPass is done, when assertions are enabled, use
160 // RefreshCallGraph to verify that the callgraph was correctly updated.
161#ifndef NDEBUG
162 if (Changed)
163 RefreshCallGraph(CurSCC, CG, true);
164#endif
165
166 return Changed;
167 }
168
169 assert(PM->getPassManagerType() == PMT_FunctionPassManager &&
170 "Invalid CGPassManager member");
171 FPPassManager *FPP = (FPPassManager*)P;
172
173 // Run pass P on all functions in the current SCC.
174 for (CallGraphNode *CGN : CurSCC) {
175 if (Function *F = CGN->getFunction()) {
176 dumpPassInfo(P, S1: EXECUTION_MSG, S2: ON_FUNCTION_MSG, Msg: F->getName());
177 {
178 TimeRegion PassTimer(getPassTimer(FPP));
179 Changed |= FPP->runOnFunction(F&: *F);
180 }
181 F->getContext().yield();
182 }
183 }
184
185 // The function pass(es) modified the IR, they may have clobbered the
186 // callgraph.
187 if (Changed && CallGraphUpToDate) {
188 LLVM_DEBUG(dbgs() << "CGSCCPASSMGR: Pass Dirtied SCC: " << P->getPassName()
189 << '\n');
190 CallGraphUpToDate = false;
191 }
192 return Changed;
193}
194
195/// Scan the functions in the specified CFG and resync the
196/// callgraph with the call sites found in it. This is used after
197/// FunctionPasses have potentially munged the callgraph, and can be used after
198/// CallGraphSCC passes to verify that they correctly updated the callgraph.
199///
200/// This function returns true if it devirtualized an existing function call,
201/// meaning it turned an indirect call into a direct call. This happens when
202/// a function pass like GVN optimizes away stuff feeding the indirect call.
203/// This never happens in checking mode.
204bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
205 bool CheckingMode) {
206 DenseMap<Value *, CallGraphNode *> Calls;
207
208 LLVM_DEBUG(dbgs() << "CGSCCPASSMGR: Refreshing SCC with " << CurSCC.size()
209 << " nodes:\n";
210 for (CallGraphNode *CGN
211 : CurSCC) CGN->dump(););
212
213 bool MadeChange = false;
214 bool DevirtualizedCall = false;
215
216 // Scan all functions in the SCC.
217 unsigned FunctionNo = 0;
218 for (CallGraphSCC::iterator SCCIdx = CurSCC.begin(), E = CurSCC.end();
219 SCCIdx != E; ++SCCIdx, ++FunctionNo) {
220 CallGraphNode *CGN = *SCCIdx;
221 Function *F = CGN->getFunction();
222 if (!F || F->isDeclaration()) continue;
223
224 // Walk the function body looking for call sites. Sync up the call sites in
225 // CGN with those actually in the function.
226
227 // Keep track of the number of direct and indirect calls that were
228 // invalidated and removed.
229 unsigned NumDirectRemoved = 0, NumIndirectRemoved = 0;
230
231 CallGraphNode::iterator CGNEnd = CGN->end();
232
233 auto RemoveAndCheckForDone = [&](CallGraphNode::iterator I) {
234 // Just remove the edge from the set of callees, keep track of whether
235 // I points to the last element of the vector.
236 bool WasLast = I + 1 == CGNEnd;
237 CGN->removeCallEdge(I);
238
239 // If I pointed to the last element of the vector, we have to bail out:
240 // iterator checking rejects comparisons of the resultant pointer with
241 // end.
242 if (WasLast)
243 return true;
244
245 CGNEnd = CGN->end();
246 return false;
247 };
248
249 // Get the set of call sites currently in the function.
250 for (CallGraphNode::iterator I = CGN->begin(); I != CGNEnd;) {
251 // Delete "reference" call records that do not have call instruction. We
252 // reinsert them as needed later. However, keep them in checking mode.
253 if (!I->first) {
254 if (CheckingMode) {
255 ++I;
256 continue;
257 }
258 if (RemoveAndCheckForDone(I))
259 break;
260 continue;
261 }
262
263 // If this call site is null, then the function pass deleted the call
264 // entirely and the WeakTrackingVH nulled it out.
265 auto *Call = dyn_cast_or_null<CallBase>(Val&: *I->first);
266 if (!Call ||
267 // If we've already seen this call site, then the FunctionPass RAUW'd
268 // one call with another, which resulted in two "uses" in the edge
269 // list of the same call.
270 Calls.count(Val: Call)) {
271 assert(!CheckingMode &&
272 "CallGraphSCCPass did not update the CallGraph correctly!");
273
274 // If this was an indirect call site, count it.
275 if (!I->second->getFunction())
276 ++NumIndirectRemoved;
277 else
278 ++NumDirectRemoved;
279
280 if (RemoveAndCheckForDone(I))
281 break;
282 continue;
283 }
284
285 assert(!Calls.count(Call) && "Call site occurs in node multiple times");
286
287 if (Call) {
288 Function *Callee = Call->getCalledFunction();
289 // Ignore intrinsics because they're not really function calls.
290 if (!Callee || !(Callee->isIntrinsic()))
291 Calls.insert(KV: std::make_pair(x&: Call, y&: I->second));
292 }
293 ++I;
294 }
295
296 // Loop over all of the instructions in the function, getting the callsites.
297 // Keep track of the number of direct/indirect calls added.
298 unsigned NumDirectAdded = 0, NumIndirectAdded = 0;
299
300 for (BasicBlock &BB : *F)
301 for (Instruction &I : BB) {
302 auto *Call = dyn_cast<CallBase>(Val: &I);
303 if (!Call)
304 continue;
305 Function *Callee = Call->getCalledFunction();
306 if (Callee && Callee->isIntrinsic())
307 continue;
308
309 // If we are not in checking mode, insert potential callback calls as
310 // references. This is not a requirement but helps to iterate over the
311 // functions in the right order.
312 if (!CheckingMode) {
313 forEachCallbackFunction(CB: *Call, Func: [&](Function *CB) {
314 CGN->addCalledFunction(Call: nullptr, M: CG.getOrInsertFunction(F: CB));
315 });
316 }
317
318 // If this call site already existed in the callgraph, just verify it
319 // matches up to expectations and remove it from Calls.
320 DenseMap<Value *, CallGraphNode *>::iterator ExistingIt =
321 Calls.find(Val: Call);
322 if (ExistingIt != Calls.end()) {
323 CallGraphNode *ExistingNode = ExistingIt->second;
324
325 // Remove from Calls since we have now seen it.
326 Calls.erase(I: ExistingIt);
327
328 // Verify that the callee is right.
329 if (ExistingNode->getFunction() == Call->getCalledFunction())
330 continue;
331
332 // If we are in checking mode, we are not allowed to actually mutate
333 // the callgraph. If this is a case where we can infer that the
334 // callgraph is less precise than it could be (e.g. an indirect call
335 // site could be turned direct), don't reject it in checking mode, and
336 // don't tweak it to be more precise.
337 if (CheckingMode && Call->getCalledFunction() &&
338 ExistingNode->getFunction() == nullptr)
339 continue;
340
341 assert(!CheckingMode &&
342 "CallGraphSCCPass did not update the CallGraph correctly!");
343
344 // If not, we either went from a direct call to indirect, indirect to
345 // direct, or direct to different direct.
346 CallGraphNode *CalleeNode;
347 if (Function *Callee = Call->getCalledFunction()) {
348 CalleeNode = CG.getOrInsertFunction(F: Callee);
349 // Keep track of whether we turned an indirect call into a direct
350 // one.
351 if (!ExistingNode->getFunction()) {
352 DevirtualizedCall = true;
353 LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Devirtualized call to '"
354 << Callee->getName() << "'\n");
355 }
356 } else {
357 CalleeNode = CG.getCallsExternalNode();
358 }
359
360 // Update the edge target in CGN.
361 CGN->replaceCallEdge(Call&: *Call, NewCall&: *Call, NewNode: CalleeNode);
362 MadeChange = true;
363 continue;
364 }
365
366 assert(!CheckingMode &&
367 "CallGraphSCCPass did not update the CallGraph correctly!");
368
369 // If the call site didn't exist in the CGN yet, add it.
370 CallGraphNode *CalleeNode;
371 if (Function *Callee = Call->getCalledFunction()) {
372 CalleeNode = CG.getOrInsertFunction(F: Callee);
373 ++NumDirectAdded;
374 } else {
375 CalleeNode = CG.getCallsExternalNode();
376 ++NumIndirectAdded;
377 }
378
379 CGN->addCalledFunction(Call, M: CalleeNode);
380 MadeChange = true;
381 }
382
383 // We scanned the old callgraph node, removing invalidated call sites and
384 // then added back newly found call sites. One thing that can happen is
385 // that an old indirect call site was deleted and replaced with a new direct
386 // call. In this case, we have devirtualized a call, and CGSCCPM would like
387 // to iteratively optimize the new code. Unfortunately, we don't really
388 // have a great way to detect when this happens. As an approximation, we
389 // just look at whether the number of indirect calls is reduced and the
390 // number of direct calls is increased. There are tons of ways to fool this
391 // (e.g. DCE'ing an indirect call and duplicating an unrelated block with a
392 // direct call) but this is close enough.
393 if (NumIndirectRemoved > NumIndirectAdded &&
394 NumDirectRemoved < NumDirectAdded)
395 DevirtualizedCall = true;
396
397 // After scanning this function, if we still have entries in callsites, then
398 // they are dangling pointers. WeakTrackingVH should save us for this, so
399 // abort if
400 // this happens.
401 assert(Calls.empty() && "Dangling pointers found in call sites map");
402
403 // Periodically do an explicit clear to remove tombstones when processing
404 // large scc's.
405 if ((FunctionNo & 15) == 15)
406 Calls.clear();
407 }
408
409 LLVM_DEBUG(if (MadeChange) {
410 dbgs() << "CGSCCPASSMGR: Refreshed SCC is now:\n";
411 for (CallGraphNode *CGN : CurSCC)
412 CGN->dump();
413 if (DevirtualizedCall)
414 dbgs() << "CGSCCPASSMGR: Refresh devirtualized a call!\n";
415 } else {
416 dbgs() << "CGSCCPASSMGR: SCC Refresh didn't change call graph.\n";
417 });
418 (void)MadeChange;
419
420 return DevirtualizedCall;
421}
422
423/// Execute the body of the entire pass manager on the specified SCC.
424/// This keeps track of whether a function pass devirtualizes
425/// any calls and returns it in DevirtualizedCall.
426bool CGPassManager::RunAllPassesOnSCC(CallGraphSCC &CurSCC, CallGraph &CG,
427 bool &DevirtualizedCall) {
428 bool Changed = false;
429
430 // Keep track of whether the callgraph is known to be up-to-date or not.
431 // The CGSSC pass manager runs two types of passes:
432 // CallGraphSCC Passes and other random function passes. Because other
433 // random function passes are not CallGraph aware, they may clobber the
434 // call graph by introducing new calls or deleting other ones. This flag
435 // is set to false when we run a function pass so that we know to clean up
436 // the callgraph when we need to run a CGSCCPass again.
437 bool CallGraphUpToDate = true;
438
439 // Run all passes on current SCC.
440 for (unsigned PassNo = 0, e = getNumContainedPasses();
441 PassNo != e; ++PassNo) {
442 Pass *P = getContainedPass(N: PassNo);
443
444 // If we're in -debug-pass=Executions mode, construct the SCC node list,
445 // otherwise avoid constructing this string as it is expensive.
446 if (isPassDebuggingExecutionsOrMore()) {
447 std::string Functions;
448 #ifndef NDEBUG
449 raw_string_ostream OS(Functions);
450 ListSeparator LS;
451 for (const CallGraphNode *CGN : CurSCC) {
452 OS << LS;
453 CGN->print(OS);
454 }
455 #endif
456 dumpPassInfo(P, S1: EXECUTION_MSG, S2: ON_CG_MSG, Msg: Functions);
457 }
458 dumpRequiredSet(P);
459
460 initializeAnalysisImpl(P);
461
462#ifdef EXPENSIVE_CHECKS
463 uint64_t RefHash = P->structuralHash(CG.getModule());
464#endif
465
466 // Actually run this pass on the current SCC.
467 bool LocalChanged =
468 RunPassOnSCC(P, CurSCC, CG, CallGraphUpToDate, DevirtualizedCall);
469
470 Changed |= LocalChanged;
471
472#ifdef EXPENSIVE_CHECKS
473 if (!LocalChanged && (RefHash != P->structuralHash(CG.getModule()))) {
474 llvm::errs() << "Pass modifies its input and doesn't report it: "
475 << P->getPassName() << "\n";
476 llvm_unreachable("Pass modifies its input and doesn't report it");
477 }
478#endif
479 if (LocalChanged)
480 dumpPassInfo(P, S1: MODIFICATION_MSG, S2: ON_CG_MSG, Msg: "");
481 dumpPreservedSet(P);
482
483 verifyPreservedAnalysis(P);
484 if (LocalChanged)
485 removeNotPreservedAnalysis(P);
486 recordAvailableAnalysis(P);
487 removeDeadPasses(P, Msg: "", ON_CG_MSG);
488 }
489
490 // If the callgraph was left out of date (because the last pass run was a
491 // functionpass), refresh it before we move on to the next SCC.
492 if (!CallGraphUpToDate)
493 DevirtualizedCall |= RefreshCallGraph(CurSCC, CG, CheckingMode: false);
494 return Changed;
495}
496
497/// Execute all of the passes scheduled for execution. Keep track of
498/// whether any of the passes modifies the module, and if so, return true.
499bool CGPassManager::runOnModule(Module &M) {
500 CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
501 bool Changed = doInitialization(CG);
502
503 // Walk the callgraph in bottom-up SCC order.
504 scc_iterator<CallGraph*> CGI = scc_begin(G: &CG);
505
506 CallGraphSCC CurSCC(CG, &CGI);
507 while (!CGI.isAtEnd()) {
508 // Copy the current SCC and increment past it so that the pass can hack
509 // on the SCC if it wants to without invalidating our iterator.
510 const std::vector<CallGraphNode *> &NodeVec = *CGI;
511 CurSCC.initialize(NewNodes: NodeVec);
512 ++CGI;
513
514 // At the top level, we run all the passes in this pass manager on the
515 // functions in this SCC. However, we support iterative compilation in the
516 // case where a function pass devirtualizes a call to a function. For
517 // example, it is very common for a function pass (often GVN or instcombine)
518 // to eliminate the addressing that feeds into a call. With that improved
519 // information, we would like the call to be an inline candidate, infer
520 // mod-ref information etc.
521 //
522 // Because of this, we allow iteration up to a specified iteration count.
523 // This only happens in the case of a devirtualized call, so we only burn
524 // compile time in the case that we're making progress. We also have a hard
525 // iteration count limit in case there is crazy code.
526 unsigned Iteration = 0;
527 bool DevirtualizedCall = false;
528 do {
529 LLVM_DEBUG(if (Iteration) dbgs()
530 << " SCCPASSMGR: Re-visiting SCC, iteration #" << Iteration
531 << '\n');
532 DevirtualizedCall = false;
533 Changed |= RunAllPassesOnSCC(CurSCC, CG, DevirtualizedCall);
534 } while (Iteration++ < MaxDevirtIterations && DevirtualizedCall);
535
536 if (DevirtualizedCall)
537 LLVM_DEBUG(dbgs() << " CGSCCPASSMGR: Stopped iteration after "
538 << Iteration
539 << " times, due to -max-devirt-iterations\n");
540
541 MaxSCCIterations.updateMax(V: Iteration);
542 }
543 Changed |= doFinalization(CG);
544 return Changed;
545}
546
547/// Initialize CG
548bool CGPassManager::doInitialization(CallGraph &CG) {
549 bool Changed = false;
550 for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) {
551 if (PMDataManager *PM = getContainedPass(N: i)->getAsPMDataManager()) {
552 assert(PM->getPassManagerType() == PMT_FunctionPassManager &&
553 "Invalid CGPassManager member");
554 Changed |= ((FPPassManager*)PM)->doInitialization(M&: CG.getModule());
555 } else {
556 Changed |= ((CallGraphSCCPass*)getContainedPass(N: i))->doInitialization(CG);
557 }
558 }
559 return Changed;
560}
561
562/// Finalize CG
563bool CGPassManager::doFinalization(CallGraph &CG) {
564 bool Changed = false;
565 for (unsigned i = 0, e = getNumContainedPasses(); i != e; ++i) {
566 if (PMDataManager *PM = getContainedPass(N: i)->getAsPMDataManager()) {
567 assert(PM->getPassManagerType() == PMT_FunctionPassManager &&
568 "Invalid CGPassManager member");
569 Changed |= ((FPPassManager*)PM)->doFinalization(M&: CG.getModule());
570 } else {
571 Changed |= ((CallGraphSCCPass*)getContainedPass(N: i))->doFinalization(CG);
572 }
573 }
574 return Changed;
575}
576
577//===----------------------------------------------------------------------===//
578// CallGraphSCC Implementation
579//===----------------------------------------------------------------------===//
580
581/// This informs the SCC and the pass manager that the specified
582/// Old node has been deleted, and New is to be used in its place.
583void CallGraphSCC::ReplaceNode(CallGraphNode *Old, CallGraphNode *New) {
584 assert(Old != New && "Should not replace node with self");
585 for (unsigned i = 0; ; ++i) {
586 assert(i != Nodes.size() && "Node not in SCC");
587 if (Nodes[i] != Old) continue;
588 if (New)
589 Nodes[i] = New;
590 else
591 Nodes.erase(position: Nodes.begin() + i);
592 break;
593 }
594
595 // Update the active scc_iterator so that it doesn't contain dangling
596 // pointers to the old CallGraphNode.
597 scc_iterator<CallGraph*> *CGI = (scc_iterator<CallGraph*>*)Context;
598 CGI->ReplaceNode(Old, New);
599}
600
601void CallGraphSCC::DeleteNode(CallGraphNode *Old) {
602 ReplaceNode(Old, /*New=*/nullptr);
603}
604
605//===----------------------------------------------------------------------===//
606// CallGraphSCCPass Implementation
607//===----------------------------------------------------------------------===//
608
609/// Assign pass manager to manage this pass.
610void CallGraphSCCPass::assignPassManager(PMStack &PMS,
611 PassManagerType PreferredType) {
612 // Find CGPassManager
613 while (!PMS.empty() &&
614 PMS.top()->getPassManagerType() > PMT_CallGraphPassManager)
615 PMS.pop();
616
617 assert(!PMS.empty() && "Unable to handle Call Graph Pass");
618 CGPassManager *CGP;
619
620 if (PMS.top()->getPassManagerType() == PMT_CallGraphPassManager)
621 CGP = (CGPassManager*)PMS.top();
622 else {
623 // Create new Call Graph SCC Pass Manager if it does not exist.
624 assert(!PMS.empty() && "Unable to create Call Graph Pass Manager");
625 PMDataManager *PMD = PMS.top();
626
627 // [1] Create new Call Graph Pass Manager
628 CGP = new CGPassManager();
629
630 // [2] Set up new manager's top level manager
631 PMTopLevelManager *TPM = PMD->getTopLevelManager();
632 TPM->addIndirectPassManager(Manager: CGP);
633
634 // [3] Assign manager to manage this new manager. This may create
635 // and push new managers into PMS
636 Pass *P = CGP;
637 TPM->schedulePass(P);
638
639 // [4] Push new manager into PMS
640 PMS.push(PM: CGP);
641 }
642
643 CGP->add(P: this);
644}
645
646/// For this class, we declare that we require and preserve the call graph.
647/// If the derived class implements this method, it should
648/// always explicitly call the implementation here.
649void CallGraphSCCPass::getAnalysisUsage(AnalysisUsage &AU) const {
650 AU.addRequired<CallGraphWrapperPass>();
651 AU.addPreserved<CallGraphWrapperPass>();
652}
653
654//===----------------------------------------------------------------------===//
655// PrintCallGraphPass Implementation
656//===----------------------------------------------------------------------===//
657
658namespace {
659
660 /// PrintCallGraphPass - Print a Module corresponding to a call graph.
661 ///
662 class PrintCallGraphPass : public CallGraphSCCPass {
663 std::string Banner;
664 raw_ostream &OS; // raw_ostream to print on.
665
666 public:
667 static char ID;
668
669 PrintCallGraphPass(const std::string &B, raw_ostream &OS)
670 : CallGraphSCCPass(ID), Banner(B), OS(OS) {}
671
672 void getAnalysisUsage(AnalysisUsage &AU) const override {
673 AU.setPreservesAll();
674 }
675
676 bool runOnSCC(CallGraphSCC &SCC) override {
677 bool BannerPrinted = false;
678 auto PrintBannerOnce = [&]() {
679 if (BannerPrinted)
680 return;
681 OS << Banner;
682 BannerPrinted = true;
683 };
684
685 bool NeedModule = llvm::forcePrintModuleIR();
686 if (isFunctionInPrintList(FunctionName: "*") && NeedModule) {
687 PrintBannerOnce();
688 OS << "\n";
689 SCC.getCallGraph().getModule().print(OS, AAW: nullptr);
690 return false;
691 }
692 bool FoundFunction = false;
693 for (CallGraphNode *CGN : SCC) {
694 if (Function *F = CGN->getFunction()) {
695 if (!F->isDeclaration() && isFunctionInPrintList(FunctionName: F->getName())) {
696 FoundFunction = true;
697 if (!NeedModule) {
698 PrintBannerOnce();
699 F->print(OS);
700 }
701 }
702 } else if (isFunctionInPrintList(FunctionName: "*")) {
703 PrintBannerOnce();
704 OS << "\nPrinting <null> Function\n";
705 }
706 }
707 if (NeedModule && FoundFunction) {
708 PrintBannerOnce();
709 OS << "\n";
710 SCC.getCallGraph().getModule().print(OS, AAW: nullptr);
711 }
712 return false;
713 }
714
715 StringRef getPassName() const override { return "Print CallGraph IR"; }
716 };
717
718} // end anonymous namespace.
719
720char PrintCallGraphPass::ID = 0;
721
722Pass *CallGraphSCCPass::createPrinterPass(raw_ostream &OS,
723 const std::string &Banner) const {
724 return new PrintCallGraphPass(Banner, OS);
725}
726
727char DummyCGSCCPass::ID = 0;
728
729INITIALIZE_PASS(DummyCGSCCPass, "DummyCGSCCPass", "DummyCGSCCPass", false,
730 false)
731