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LazyCallGraph.h
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1//===- LazyCallGraph.h - Analysis of a Module's call graph ------*- C++ -*-===//
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/// \file
9///
10/// Implements a lazy call graph analysis and related passes for the new pass
11/// manager.
12///
13/// NB: This is *not* a traditional call graph! It is a graph which models both
14/// the current calls and potential calls. As a consequence there are many
15/// edges in this call graph that do not correspond to a 'call' or 'invoke'
16/// instruction.
17///
18/// The primary use cases of this graph analysis is to facilitate iterating
19/// across the functions of a module in ways that ensure all callees are
20/// visited prior to a caller (given any SCC constraints), or vice versa. As
21/// such is it particularly well suited to organizing CGSCC optimizations such
22/// as inlining, outlining, argument promotion, etc. That is its primary use
23/// case and motivates the design. It may not be appropriate for other
24/// purposes. The use graph of functions or some other conservative analysis of
25/// call instructions may be interesting for optimizations and subsequent
26/// analyses which don't work in the context of an overly specified
27/// potential-call-edge graph.
28///
29/// To understand the specific rules and nature of this call graph analysis,
30/// see the documentation of the \c LazyCallGraph below.
31///
32//===----------------------------------------------------------------------===//
33
34#ifndef LLVM_ANALYSIS_LAZYCALLGRAPH_H
35#define LLVM_ANALYSIS_LAZYCALLGRAPH_H
36
37#include "llvm/ADT/ArrayRef.h"
38#include "llvm/ADT/DenseMap.h"
40#include "llvm/ADT/SetVector.h"
42#include "llvm/ADT/StringRef.h"
43#include "llvm/ADT/iterator.h"
46#include "llvm/IR/PassManager.h"
49#include <cassert>
50#include <iterator>
51#include <optional>
52#include <string>
53#include <utility>
54
55namespace llvm {
56
57class Constant;
58class Function;
59template <class GraphType> struct GraphTraits;
60class Module;
61class TargetLibraryInfo;
62class Value;
63
64/// A lazily constructed view of the call graph of a module.
65///
66/// With the edges of this graph, the motivating constraint that we are
67/// attempting to maintain is that function-local optimization, CGSCC-local
68/// optimizations, and optimizations transforming a pair of functions connected
69/// by an edge in the graph, do not invalidate a bottom-up traversal of the SCC
70/// DAG. That is, no optimizations will delete, remove, or add an edge such
71/// that functions already visited in a bottom-up order of the SCC DAG are no
72/// longer valid to have visited, or such that functions not yet visited in
73/// a bottom-up order of the SCC DAG are not required to have already been
74/// visited.
75///
76/// Within this constraint, the desire is to minimize the merge points of the
77/// SCC DAG. The greater the fanout of the SCC DAG and the fewer merge points
78/// in the SCC DAG, the more independence there is in optimizing within it.
79/// There is a strong desire to enable parallelization of optimizations over
80/// the call graph, and both limited fanout and merge points will (artificially
81/// in some cases) limit the scaling of such an effort.
82///
83/// To this end, graph represents both direct and any potential resolution to
84/// an indirect call edge. Another way to think about it is that it represents
85/// both the direct call edges and any direct call edges that might be formed
86/// through static optimizations. Specifically, it considers taking the address
87/// of a function to be an edge in the call graph because this might be
88/// forwarded to become a direct call by some subsequent function-local
89/// optimization. The result is that the graph closely follows the use-def
90/// edges for functions. Walking "up" the graph can be done by looking at all
91/// of the uses of a function.
92///
93/// The roots of the call graph are the external functions and functions
94/// escaped into global variables. Those functions can be called from outside
95/// of the module or via unknowable means in the IR -- we may not be able to
96/// form even a potential call edge from a function body which may dynamically
97/// load the function and call it.
98///
99/// This analysis still requires updates to remain valid after optimizations
100/// which could potentially change the set of potential callees. The
101/// constraints it operates under only make the traversal order remain valid.
102///
103/// The entire analysis must be re-computed if full interprocedural
104/// optimizations run at any point. For example, globalopt completely
105/// invalidates the information in this analysis.
106///
107/// FIXME: This class is named LazyCallGraph in a lame attempt to distinguish
108/// it from the existing CallGraph. At some point, it is expected that this
109/// will be the only call graph and it will be renamed accordingly.
111public:
112 class Node;
113 class EdgeSequence;
114 class SCC;
115 class RefSCC;
116
117 /// A class used to represent edges in the call graph.
118 ///
119 /// The lazy call graph models both *call* edges and *reference* edges. Call
120 /// edges are much what you would expect, and exist when there is a 'call' or
121 /// 'invoke' instruction of some function. Reference edges are also tracked
122 /// along side these, and exist whenever any instruction (transitively
123 /// through its operands) references a function. All call edges are
124 /// inherently reference edges, and so the reference graph forms a superset
125 /// of the formal call graph.
126 ///
127 /// All of these forms of edges are fundamentally represented as outgoing
128 /// edges. The edges are stored in the source node and point at the target
129 /// node. This allows the edge structure itself to be a very compact data
130 /// structure: essentially a tagged pointer.
131 class Edge {
132 public:
133 /// The kind of edge in the graph.
134 enum Kind : bool { Ref = false, Call = true };
135
137 explicit Edge(Node &N, Kind K);
138
139 /// Test whether the edge is null.
140 ///
141 /// This happens when an edge has been deleted. We leave the edge objects
142 /// around but clear them.
143 explicit operator bool() const;
144
145 /// Returns the \c Kind of the edge.
146 Kind getKind() const;
147
148 /// Test whether the edge represents a direct call to a function.
149 ///
150 /// This requires that the edge is not null.
151 bool isCall() const;
152
153 /// Get the call graph node referenced by this edge.
154 ///
155 /// This requires that the edge is not null.
156 Node &getNode() const;
157
158 /// Get the function referenced by this edge.
159 ///
160 /// This requires that the edge is not null.
161 Function &getFunction() const;
162
163 private:
166
168
169 void setKind(Kind K) { Value.setInt(K); }
170 };
171
172 /// The edge sequence object.
173 ///
174 /// This typically exists entirely within the node but is exposed as
175 /// a separate type because a node doesn't initially have edges. An explicit
176 /// population step is required to produce this sequence at first and it is
177 /// then cached in the node. It is also used to represent edges entering the
178 /// graph from outside the module to model the graph's roots.
179 ///
180 /// The sequence itself both iterable and indexable. The indexes remain
181 /// stable even as the sequence mutates (including removal).
183 friend class LazyCallGraph;
186
189
190 public:
191 /// An iterator used for the edges to both entry nodes and child nodes.
193 : public iterator_adaptor_base<iterator, VectorImplT::iterator,
194 std::forward_iterator_tag> {
195 friend class LazyCallGraph;
197
199
200 // Build the iterator for a specific position in the edge list.
202 : iterator_adaptor_base(BaseI), E(E) {
203 while (I != E && !*I)
204 ++I;
205 }
206
207 public:
208 iterator() = default;
209
210 using iterator_adaptor_base::operator++;
212 do {
213 ++I;
214 } while (I != E && !*I);
215 return *this;
216 }
217 };
218
219 /// An iterator over specifically call edges.
220 ///
221 /// This has the same iteration properties as the \c iterator, but
222 /// restricts itself to edges which represent actual calls.
224 : public iterator_adaptor_base<call_iterator, VectorImplT::iterator,
225 std::forward_iterator_tag> {
226 friend class LazyCallGraph;
228
230
231 /// Advance the iterator to the next valid, call edge.
232 void advanceToNextEdge() {
233 while (I != E && (!*I || !I->isCall()))
234 ++I;
235 }
236
237 // Build the iterator for a specific position in the edge list.
239 : iterator_adaptor_base(BaseI), E(E) {
240 advanceToNextEdge();
241 }
242
243 public:
244 call_iterator() = default;
245
246 using iterator_adaptor_base::operator++;
248 ++I;
249 advanceToNextEdge();
250 return *this;
251 }
252 };
253
254 iterator begin() { return iterator(Edges.begin(), Edges.end()); }
255 iterator end() { return iterator(Edges.end(), Edges.end()); }
256
258 assert(EdgeIndexMap.find(&N) != EdgeIndexMap.end() && "No such edge!");
259 auto &E = Edges[EdgeIndexMap.find(&N)->second];
260 assert(E && "Dead or null edge!");
261 return E;
262 }
263
265 auto EI = EdgeIndexMap.find(&N);
266 if (EI == EdgeIndexMap.end())
267 return nullptr;
268 auto &E = Edges[EI->second];
269 return E ? &E : nullptr;
270 }
271
273 return call_iterator(Edges.begin(), Edges.end());
274 }
275 call_iterator call_end() { return call_iterator(Edges.end(), Edges.end()); }
276
278 return make_range(call_begin(), call_end());
279 }
280
281 bool empty() {
282 for (auto &E : Edges)
283 if (E)
284 return false;
285
286 return true;
287 }
288
289 private:
290 VectorT Edges;
291 DenseMap<Node *, int> EdgeIndexMap;
292
293 EdgeSequence() = default;
294
295 /// Internal helper to insert an edge to a node.
296 void insertEdgeInternal(Node &ChildN, Edge::Kind EK);
297
298 /// Internal helper to change an edge kind.
299 void setEdgeKind(Node &ChildN, Edge::Kind EK);
300
301 /// Internal helper to remove the edge to the given function.
302 bool removeEdgeInternal(Node &ChildN);
303 };
304
305 /// A node in the call graph.
306 ///
307 /// This represents a single node. Its primary roles are to cache the list of
308 /// callees, de-duplicate and provide fast testing of whether a function is a
309 /// callee, and facilitate iteration of child nodes in the graph.
310 ///
311 /// The node works much like an optional in order to lazily populate the
312 /// edges of each node. Until populated, there are no edges. Once populated,
313 /// you can access the edges by dereferencing the node or using the `->`
314 /// operator as if the node was an `std::optional<EdgeSequence>`.
315 class Node {
316 friend class LazyCallGraph;
318
319 public:
320 LazyCallGraph &getGraph() const { return *G; }
321
322 Function &getFunction() const { return *F; }
323
324 StringRef getName() const { return F->getName(); }
325
326 /// Equality is defined as address equality.
327 bool operator==(const Node &N) const { return this == &N; }
328 bool operator!=(const Node &N) const { return !operator==(N); }
329
330 /// Tests whether the node has been populated with edges.
331 bool isPopulated() const { return Edges.has_value(); }
332
333 /// Tests whether this is actually a dead node and no longer valid.
334 ///
335 /// Users rarely interact with nodes in this state and other methods are
336 /// invalid. This is used to model a node in an edge list where the
337 /// function has been completely removed.
338 bool isDead() const {
339 assert(!G == !F &&
340 "Both graph and function pointers should be null or non-null.");
341 return !G;
342 }
343
344 // We allow accessing the edges by dereferencing or using the arrow
345 // operator, essentially wrapping the internal optional.
347 // Rip const off because the node itself isn't changing here.
348 return const_cast<EdgeSequence &>(*Edges);
349 }
350 EdgeSequence *operator->() const { return &**this; }
351
352 /// Populate the edges of this node if necessary.
353 ///
354 /// The first time this is called it will populate the edges for this node
355 /// in the graph. It does this by scanning the underlying function, so once
356 /// this is done, any changes to that function must be explicitly reflected
357 /// in updates to the graph.
358 ///
359 /// \returns the populated \c EdgeSequence to simplify walking it.
360 ///
361 /// This will not update or re-scan anything if called repeatedly. Instead,
362 /// the edge sequence is cached and returned immediately on subsequent
363 /// calls.
365 if (Edges)
366 return *Edges;
367
368 return populateSlow();
369 }
370
371 private:
373 Function *F;
374
375 // We provide for the DFS numbering and Tarjan walk lowlink numbers to be
376 // stored directly within the node. These are both '-1' when nodes are part
377 // of an SCC (or RefSCC), or '0' when not yet reached in a DFS walk.
378 int DFSNumber = 0;
379 int LowLink = 0;
380
381 std::optional<EdgeSequence> Edges;
382
383 /// Basic constructor implements the scanning of F into Edges and
384 /// EdgeIndexMap.
385 Node(LazyCallGraph &G, Function &F) : G(&G), F(&F) {}
386
387 /// Implementation of the scan when populating.
388 EdgeSequence &populateSlow();
389
390 /// Internal helper to directly replace the function with a new one.
391 ///
392 /// This is used to facilitate transformations which need to replace the
393 /// formal Function object but directly move the body and users from one to
394 /// the other.
395 void replaceFunction(Function &NewF);
396
397 void clear() { Edges.reset(); }
398
399 /// Print the name of this node's function.
400 friend raw_ostream &operator<<(raw_ostream &OS, const Node &N) {
401 return OS << N.F->getName();
402 }
403
404 /// Dump the name of this node's function to stderr.
405 void dump() const;
406 };
407
408 /// An SCC of the call graph.
409 ///
410 /// This represents a Strongly Connected Component of the direct call graph
411 /// -- ignoring indirect calls and function references. It stores this as
412 /// a collection of call graph nodes. While the order of nodes in the SCC is
413 /// stable, it is not any particular order.
414 ///
415 /// The SCCs are nested within a \c RefSCC, see below for details about that
416 /// outer structure. SCCs do not support mutation of the call graph, that
417 /// must be done through the containing \c RefSCC in order to fully reason
418 /// about the ordering and connections of the graph.
420 friend class LazyCallGraph;
422
423 RefSCC *OuterRefSCC;
425
426 template <typename NodeRangeT>
427 SCC(RefSCC &OuterRefSCC, NodeRangeT &&Nodes)
428 : OuterRefSCC(&OuterRefSCC), Nodes(std::forward<NodeRangeT>(Nodes)) {}
429
430 void clear() {
431 OuterRefSCC = nullptr;
432 Nodes.clear();
433 }
434
435 /// Print a short description useful for debugging or logging.
436 ///
437 /// We print the function names in the SCC wrapped in '()'s and skipping
438 /// the middle functions if there are a large number.
439 //
440 // Note: this is defined inline to dodge issues with GCC's interpretation
441 // of enclosing namespaces for friend function declarations.
442 friend raw_ostream &operator<<(raw_ostream &OS, const SCC &C) {
443 OS << '(';
444 int I = 0;
445 for (LazyCallGraph::Node &N : C) {
446 if (I > 0)
447 OS << ", ";
448 // Elide the inner elements if there are too many.
449 if (I > 8) {
450 OS << "..., " << *C.Nodes.back();
451 break;
452 }
453 OS << N;
454 ++I;
455 }
456 OS << ')';
457 return OS;
458 }
459
460 /// Dump a short description of this SCC to stderr.
461 void dump() const;
462
463#if !defined(NDEBUG) || defined(EXPENSIVE_CHECKS)
464 /// Verify invariants about the SCC.
465 ///
466 /// This will attempt to validate all of the basic invariants within an
467 /// SCC, but not that it is a strongly connected component per se.
468 /// Primarily useful while building and updating the graph to check that
469 /// basic properties are in place rather than having inexplicable crashes
470 /// later.
471 void verify();
472#endif
473
474 public:
476
477 iterator begin() const { return Nodes.begin(); }
478 iterator end() const { return Nodes.end(); }
479
480 int size() const { return Nodes.size(); }
481
482 RefSCC &getOuterRefSCC() const { return *OuterRefSCC; }
483
484 /// Test if this SCC is a parent of \a C.
485 ///
486 /// Note that this is linear in the number of edges departing the current
487 /// SCC.
488 bool isParentOf(const SCC &C) const;
489
490 /// Test if this SCC is an ancestor of \a C.
491 ///
492 /// Note that in the worst case this is linear in the number of edges
493 /// departing the current SCC and every SCC in the entire graph reachable
494 /// from this SCC. Thus this very well may walk every edge in the entire
495 /// call graph! Do not call this in a tight loop!
496 bool isAncestorOf(const SCC &C) const;
497
498 /// Test if this SCC is a child of \a C.
499 ///
500 /// See the comments for \c isParentOf for detailed notes about the
501 /// complexity of this routine.
502 bool isChildOf(const SCC &C) const { return C.isParentOf(*this); }
503
504 /// Test if this SCC is a descendant of \a C.
505 ///
506 /// See the comments for \c isParentOf for detailed notes about the
507 /// complexity of this routine.
508 bool isDescendantOf(const SCC &C) const { return C.isAncestorOf(*this); }
509
510 /// Provide a short name by printing this SCC to a std::string.
511 ///
512 /// This copes with the fact that we don't have a name per se for an SCC
513 /// while still making the use of this in debugging and logging useful.
514 std::string getName() const {
515 std::string Name;
517 OS << *this;
518 OS.flush();
519 return Name;
520 }
521 };
522
523 /// A RefSCC of the call graph.
524 ///
525 /// This models a Strongly Connected Component of function reference edges in
526 /// the call graph. As opposed to actual SCCs, these can be used to scope
527 /// subgraphs of the module which are independent from other subgraphs of the
528 /// module because they do not reference it in any way. This is also the unit
529 /// where we do mutation of the graph in order to restrict mutations to those
530 /// which don't violate this independence.
531 ///
532 /// A RefSCC contains a DAG of actual SCCs. All the nodes within the RefSCC
533 /// are necessarily within some actual SCC that nests within it. Since
534 /// a direct call *is* a reference, there will always be at least one RefSCC
535 /// around any SCC.
536 ///
537 /// Spurious ref edges, meaning ref edges that still exist in the call graph
538 /// even though the corresponding IR reference no longer exists, are allowed.
539 /// This is mostly to support argument promotion, which can modify a caller to
540 /// no longer pass a function. The only place that needs to specially handle
541 /// this is deleting a dead function/node, otherwise the dead ref edges are
542 /// automatically removed when visiting the function/node no longer containing
543 /// the ref edge.
544 class RefSCC {
545 friend class LazyCallGraph;
547
549
550 /// A postorder list of the inner SCCs.
552
553 /// A map from SCC to index in the postorder list.
555
556 /// Fast-path constructor. RefSCCs should instead be constructed by calling
557 /// formRefSCCFast on the graph itself.
559
560 void clear() {
561 SCCs.clear();
562 SCCIndices.clear();
563 }
564
565 /// Print a short description useful for debugging or logging.
566 ///
567 /// We print the SCCs wrapped in '[]'s and skipping the middle SCCs if
568 /// there are a large number.
569 //
570 // Note: this is defined inline to dodge issues with GCC's interpretation
571 // of enclosing namespaces for friend function declarations.
572 friend raw_ostream &operator<<(raw_ostream &OS, const RefSCC &RC) {
573 OS << '[';
574 int I = 0;
575 for (LazyCallGraph::SCC &C : RC) {
576 if (I > 0)
577 OS << ", ";
578 // Elide the inner elements if there are too many.
579 if (I > 4) {
580 OS << "..., " << *RC.SCCs.back();
581 break;
582 }
583 OS << C;
584 ++I;
585 }
586 OS << ']';
587 return OS;
588 }
589
590 /// Dump a short description of this RefSCC to stderr.
591 void dump() const;
592
593#if !defined(NDEBUG) || defined(EXPENSIVE_CHECKS)
594 /// Verify invariants about the RefSCC and all its SCCs.
595 ///
596 /// This will attempt to validate all of the invariants *within* the
597 /// RefSCC, but not that it is a strongly connected component of the larger
598 /// graph. This makes it useful even when partially through an update.
599 ///
600 /// Invariants checked:
601 /// - SCCs and their indices match.
602 /// - The SCCs list is in fact in post-order.
603 void verify();
604#endif
605
606 public:
611
612 iterator begin() const { return SCCs.begin(); }
613 iterator end() const { return SCCs.end(); }
614
615 ssize_t size() const { return SCCs.size(); }
616
617 SCC &operator[](int Idx) { return *SCCs[Idx]; }
618
619 iterator find(SCC &C) const {
620 return SCCs.begin() + SCCIndices.find(&C)->second;
621 }
622
623 /// Test if this RefSCC is a parent of \a RC.
624 ///
625 /// CAUTION: This method walks every edge in the \c RefSCC, it can be very
626 /// expensive.
627 bool isParentOf(const RefSCC &RC) const;
628
629 /// Test if this RefSCC is an ancestor of \a RC.
630 ///
631 /// CAUTION: This method walks the directed graph of edges as far as
632 /// necessary to find a possible path to the argument. In the worst case
633 /// this may walk the entire graph and can be extremely expensive.
634 bool isAncestorOf(const RefSCC &RC) const;
635
636 /// Test if this RefSCC is a child of \a RC.
637 ///
638 /// CAUTION: This method walks every edge in the argument \c RefSCC, it can
639 /// be very expensive.
640 bool isChildOf(const RefSCC &RC) const { return RC.isParentOf(*this); }
641
642 /// Test if this RefSCC is a descendant of \a RC.
643 ///
644 /// CAUTION: This method walks the directed graph of edges as far as
645 /// necessary to find a possible path from the argument. In the worst case
646 /// this may walk the entire graph and can be extremely expensive.
647 bool isDescendantOf(const RefSCC &RC) const {
648 return RC.isAncestorOf(*this);
649 }
650
651 /// Provide a short name by printing this RefSCC to a std::string.
652 ///
653 /// This copes with the fact that we don't have a name per se for an RefSCC
654 /// while still making the use of this in debugging and logging useful.
655 std::string getName() const {
656 std::string Name;
658 OS << *this;
659 OS.flush();
660 return Name;
661 }
662
663 ///@{
664 /// \name Mutation API
665 ///
666 /// These methods provide the core API for updating the call graph in the
667 /// presence of (potentially still in-flight) DFS-found RefSCCs and SCCs.
668 ///
669 /// Note that these methods sometimes have complex runtimes, so be careful
670 /// how you call them.
671
672 /// Make an existing internal ref edge into a call edge.
673 ///
674 /// This may form a larger cycle and thus collapse SCCs into TargetN's SCC.
675 /// If that happens, the optional callback \p MergedCB will be invoked (if
676 /// provided) on the SCCs being merged away prior to actually performing
677 /// the merge. Note that this will never include the target SCC as that
678 /// will be the SCC functions are merged into to resolve the cycle. Once
679 /// this function returns, these merged SCCs are not in a valid state but
680 /// the pointers will remain valid until destruction of the parent graph
681 /// instance for the purpose of clearing cached information. This function
682 /// also returns 'true' if a cycle was formed and some SCCs merged away as
683 /// a convenience.
684 ///
685 /// After this operation, both SourceN's SCC and TargetN's SCC may move
686 /// position within this RefSCC's postorder list. Any SCCs merged are
687 /// merged into the TargetN's SCC in order to preserve reachability analyses
688 /// which took place on that SCC.
690 Node &SourceN, Node &TargetN,
691 function_ref<void(ArrayRef<SCC *> MergedSCCs)> MergeCB = {});
692
693 /// Make an existing internal call edge between separate SCCs into a ref
694 /// edge.
695 ///
696 /// If SourceN and TargetN in separate SCCs within this RefSCC, changing
697 /// the call edge between them to a ref edge is a trivial operation that
698 /// does not require any structural changes to the call graph.
699 void switchTrivialInternalEdgeToRef(Node &SourceN, Node &TargetN);
700
701 /// Make an existing internal call edge within a single SCC into a ref
702 /// edge.
703 ///
704 /// Since SourceN and TargetN are part of a single SCC, this SCC may be
705 /// split up due to breaking a cycle in the call edges that formed it. If
706 /// that happens, then this routine will insert new SCCs into the postorder
707 /// list *before* the SCC of TargetN (previously the SCC of both). This
708 /// preserves postorder as the TargetN can reach all of the other nodes by
709 /// definition of previously being in a single SCC formed by the cycle from
710 /// SourceN to TargetN.
711 ///
712 /// The newly added SCCs are added *immediately* and contiguously
713 /// prior to the TargetN SCC and return the range covering the new SCCs in
714 /// the RefSCC's postorder sequence. You can directly iterate the returned
715 /// range to observe all of the new SCCs in postorder.
716 ///
717 /// Note that if SourceN and TargetN are in separate SCCs, the simpler
718 /// routine `switchTrivialInternalEdgeToRef` should be used instead.
720 Node &TargetN);
721
722 /// Make an existing outgoing ref edge into a call edge.
723 ///
724 /// Note that this is trivial as there are no cyclic impacts and there
725 /// remains a reference edge.
726 void switchOutgoingEdgeToCall(Node &SourceN, Node &TargetN);
727
728 /// Make an existing outgoing call edge into a ref edge.
729 ///
730 /// This is trivial as there are no cyclic impacts and there remains
731 /// a reference edge.
732 void switchOutgoingEdgeToRef(Node &SourceN, Node &TargetN);
733
734 /// Insert a ref edge from one node in this RefSCC to another in this
735 /// RefSCC.
736 ///
737 /// This is always a trivial operation as it doesn't change any part of the
738 /// graph structure besides connecting the two nodes.
739 ///
740 /// Note that we don't support directly inserting internal *call* edges
741 /// because that could change the graph structure and requires returning
742 /// information about what became invalid. As a consequence, the pattern
743 /// should be to first insert the necessary ref edge, and then to switch it
744 /// to a call edge if needed and handle any invalidation that results. See
745 /// the \c switchInternalEdgeToCall routine for details.
746 void insertInternalRefEdge(Node &SourceN, Node &TargetN);
747
748 /// Insert an edge whose parent is in this RefSCC and child is in some
749 /// child RefSCC.
750 ///
751 /// There must be an existing path from the \p SourceN to the \p TargetN.
752 /// This operation is inexpensive and does not change the set of SCCs and
753 /// RefSCCs in the graph.
754 void insertOutgoingEdge(Node &SourceN, Node &TargetN, Edge::Kind EK);
755
756 /// Insert an edge whose source is in a descendant RefSCC and target is in
757 /// this RefSCC.
758 ///
759 /// There must be an existing path from the target to the source in this
760 /// case.
761 ///
762 /// NB! This is has the potential to be a very expensive function. It
763 /// inherently forms a cycle in the prior RefSCC DAG and we have to merge
764 /// RefSCCs to resolve that cycle. But finding all of the RefSCCs which
765 /// participate in the cycle can in the worst case require traversing every
766 /// RefSCC in the graph. Every attempt is made to avoid that, but passes
767 /// must still exercise caution calling this routine repeatedly.
768 ///
769 /// Also note that this can only insert ref edges. In order to insert
770 /// a call edge, first insert a ref edge and then switch it to a call edge.
771 /// These are intentionally kept as separate interfaces because each step
772 /// of the operation invalidates a different set of data structures.
773 ///
774 /// This returns all the RefSCCs which were merged into the this RefSCC
775 /// (the target's). This allows callers to invalidate any cached
776 /// information.
777 ///
778 /// FIXME: We could possibly optimize this quite a bit for cases where the
779 /// caller and callee are very nearby in the graph. See comments in the
780 /// implementation for details, but that use case might impact users.
782 Node &TargetN);
783
784 /// Remove an edge whose source is in this RefSCC and target is *not*.
785 ///
786 /// This removes an inter-RefSCC edge. All inter-RefSCC edges originating
787 /// from this SCC have been fully explored by any in-flight DFS graph
788 /// formation, so this is always safe to call once you have the source
789 /// RefSCC.
790 ///
791 /// This operation does not change the cyclic structure of the graph and so
792 /// is very inexpensive. It may change the connectivity graph of the SCCs
793 /// though, so be careful calling this while iterating over them.
794 void removeOutgoingEdge(Node &SourceN, Node &TargetN);
795
796 /// Remove a list of ref edges which are entirely within this RefSCC.
797 ///
798 /// Both the \a SourceN and all of the \a TargetNs must be within this
799 /// RefSCC. Removing these edges may break cycles that form this RefSCC and
800 /// thus this operation may change the RefSCC graph significantly. In
801 /// particular, this operation will re-form new RefSCCs based on the
802 /// remaining connectivity of the graph. The following invariants are
803 /// guaranteed to hold after calling this method:
804 ///
805 /// 1) If a ref-cycle remains after removal, it leaves this RefSCC intact
806 /// and in the graph. No new RefSCCs are built.
807 /// 2) Otherwise, this RefSCC will be dead after this call and no longer in
808 /// the graph or the postorder traversal of the call graph. Any iterator
809 /// pointing at this RefSCC will become invalid.
810 /// 3) All newly formed RefSCCs will be returned and the order of the
811 /// RefSCCs returned will be a valid postorder traversal of the new
812 /// RefSCCs.
813 /// 4) No RefSCC other than this RefSCC has its member set changed (this is
814 /// inherent in the definition of removing such an edge).
815 ///
816 /// These invariants are very important to ensure that we can build
817 /// optimization pipelines on top of the CGSCC pass manager which
818 /// intelligently update the RefSCC graph without invalidating other parts
819 /// of the RefSCC graph.
820 ///
821 /// Note that we provide no routine to remove a *call* edge. Instead, you
822 /// must first switch it to a ref edge using \c switchInternalEdgeToRef.
823 /// This split API is intentional as each of these two steps can invalidate
824 /// a different aspect of the graph structure and needs to have the
825 /// invalidation handled independently.
826 ///
827 /// The runtime complexity of this method is, in the worst case, O(V+E)
828 /// where V is the number of nodes in this RefSCC and E is the number of
829 /// edges leaving the nodes in this RefSCC. Note that E includes both edges
830 /// within this RefSCC and edges from this RefSCC to child RefSCCs. Some
831 /// effort has been made to minimize the overhead of common cases such as
832 /// self-edges and edge removals which result in a spanning tree with no
833 /// more cycles.
834 [[nodiscard]] SmallVector<RefSCC *, 1>
835 removeInternalRefEdge(Node &SourceN, ArrayRef<Node *> TargetNs);
836
837 /// A convenience wrapper around the above to handle trivial cases of
838 /// inserting a new call edge.
839 ///
840 /// This is trivial whenever the target is in the same SCC as the source or
841 /// the edge is an outgoing edge to some descendant SCC. In these cases
842 /// there is no change to the cyclic structure of SCCs or RefSCCs.
843 ///
844 /// To further make calling this convenient, it also handles inserting
845 /// already existing edges.
846 void insertTrivialCallEdge(Node &SourceN, Node &TargetN);
847
848 /// A convenience wrapper around the above to handle trivial cases of
849 /// inserting a new ref edge.
850 ///
851 /// This is trivial whenever the target is in the same RefSCC as the source
852 /// or the edge is an outgoing edge to some descendant RefSCC. In these
853 /// cases there is no change to the cyclic structure of the RefSCCs.
854 ///
855 /// To further make calling this convenient, it also handles inserting
856 /// already existing edges.
857 void insertTrivialRefEdge(Node &SourceN, Node &TargetN);
858
859 /// Directly replace a node's function with a new function.
860 ///
861 /// This should be used when moving the body and users of a function to
862 /// a new formal function object but not otherwise changing the call graph
863 /// structure in any way.
864 ///
865 /// It requires that the old function in the provided node have zero uses
866 /// and the new function must have calls and references to it establishing
867 /// an equivalent graph.
868 void replaceNodeFunction(Node &N, Function &NewF);
869
870 ///@}
871 };
872
873 /// A post-order depth-first RefSCC iterator over the call graph.
874 ///
875 /// This iterator walks the cached post-order sequence of RefSCCs. However,
876 /// it trades stability for flexibility. It is restricted to a forward
877 /// iterator but will survive mutations which insert new RefSCCs and continue
878 /// to point to the same RefSCC even if it moves in the post-order sequence.
880 : public iterator_facade_base<postorder_ref_scc_iterator,
881 std::forward_iterator_tag, RefSCC> {
882 friend class LazyCallGraph;
884
885 /// Nonce type to select the constructor for the end iterator.
886 struct IsAtEndT {};
887
889 RefSCC *RC = nullptr;
890
891 /// Build the begin iterator for a node.
892 postorder_ref_scc_iterator(LazyCallGraph &G) : G(&G), RC(getRC(G, 0)) {
893 incrementUntilNonEmptyRefSCC();
894 }
895
896 /// Build the end iterator for a node. This is selected purely by overload.
897 postorder_ref_scc_iterator(LazyCallGraph &G, IsAtEndT /*Nonce*/) : G(&G) {}
898
899 /// Get the post-order RefSCC at the given index of the postorder walk,
900 /// populating it if necessary.
901 static RefSCC *getRC(LazyCallGraph &G, int Index) {
902 if (Index == (int)G.PostOrderRefSCCs.size())
903 // We're at the end.
904 return nullptr;
905
906 return G.PostOrderRefSCCs[Index];
907 }
908
909 // Keep incrementing until RC is non-empty (or null).
910 void incrementUntilNonEmptyRefSCC() {
911 while (RC && RC->size() == 0)
912 increment();
913 }
914
915 void increment() {
916 assert(RC && "Cannot increment the end iterator!");
917 RC = getRC(*G, G->RefSCCIndices.find(RC)->second + 1);
918 }
919
920 public:
922 return G == Arg.G && RC == Arg.RC;
923 }
924
925 reference operator*() const { return *RC; }
926
927 using iterator_facade_base::operator++;
929 increment();
930 incrementUntilNonEmptyRefSCC();
931 return *this;
932 }
933 };
934
935 /// Construct a graph for the given module.
936 ///
937 /// This sets up the graph and computes all of the entry points of the graph.
938 /// No function definitions are scanned until their nodes in the graph are
939 /// requested during traversal.
942
945
946 bool invalidate(Module &, const PreservedAnalyses &PA,
948
949 EdgeSequence::iterator begin() { return EntryEdges.begin(); }
950 EdgeSequence::iterator end() { return EntryEdges.end(); }
951
952 void buildRefSCCs();
953
955 if (!EntryEdges.empty())
956 assert(!PostOrderRefSCCs.empty() &&
957 "Must form RefSCCs before iterating them!");
958 return postorder_ref_scc_iterator(*this);
959 }
961 if (!EntryEdges.empty())
962 assert(!PostOrderRefSCCs.empty() &&
963 "Must form RefSCCs before iterating them!");
964 return postorder_ref_scc_iterator(*this,
965 postorder_ref_scc_iterator::IsAtEndT());
966 }
967
970 }
971
972 /// Lookup a function in the graph which has already been scanned and added.
973 Node *lookup(const Function &F) const { return NodeMap.lookup(&F); }
974
975 /// Lookup a function's SCC in the graph.
976 ///
977 /// \returns null if the function hasn't been assigned an SCC via the RefSCC
978 /// iterator walk.
979 SCC *lookupSCC(Node &N) const { return SCCMap.lookup(&N); }
980
981 /// Lookup a function's RefSCC in the graph.
982 ///
983 /// \returns null if the function hasn't been assigned a RefSCC via the
984 /// RefSCC iterator walk.
986 if (SCC *C = lookupSCC(N))
987 return &C->getOuterRefSCC();
988
989 return nullptr;
990 }
991
992 /// Get a graph node for a given function, scanning it to populate the graph
993 /// data as necessary.
995 Node *&N = NodeMap[&F];
996 if (N)
997 return *N;
998
999 return insertInto(F, N);
1000 }
1001
1002 /// Get the sequence of known and defined library functions.
1003 ///
1004 /// These functions, because they are known to LLVM, can have calls
1005 /// introduced out of thin air from arbitrary IR.
1007 return LibFunctions.getArrayRef();
1008 }
1009
1010 /// Test whether a function is a known and defined library function tracked by
1011 /// the call graph.
1012 ///
1013 /// Because these functions are known to LLVM they are specially modeled in
1014 /// the call graph and even when all IR-level references have been removed
1015 /// remain active and reachable.
1016 bool isLibFunction(Function &F) const { return LibFunctions.count(&F); }
1017
1018 ///@{
1019 /// \name Pre-SCC Mutation API
1020 ///
1021 /// These methods are only valid to call prior to forming any SCCs for this
1022 /// call graph. They can be used to update the core node-graph during
1023 /// a node-based inorder traversal that precedes any SCC-based traversal.
1024 ///
1025 /// Once you begin manipulating a call graph's SCCs, most mutation of the
1026 /// graph must be performed via a RefSCC method. There are some exceptions
1027 /// below.
1028
1029 /// Update the call graph after inserting a new edge.
1030 void insertEdge(Node &SourceN, Node &TargetN, Edge::Kind EK);
1031
1032 /// Update the call graph after inserting a new edge.
1034 return insertEdge(get(Source), get(Target), EK);
1035 }
1036
1037 /// Update the call graph after deleting an edge.
1038 void removeEdge(Node &SourceN, Node &TargetN);
1039
1040 /// Update the call graph after deleting an edge.
1042 return removeEdge(get(Source), get(Target));
1043 }
1044
1045 ///@}
1046
1047 ///@{
1048 /// \name General Mutation API
1049 ///
1050 /// There are a very limited set of mutations allowed on the graph as a whole
1051 /// once SCCs have started to be formed. These routines have strict contracts
1052 /// but may be called at any point.
1053
1054 /// Remove a dead function from the call graph (typically to delete it).
1055 ///
1056 /// Note that the function must have an empty use list, and the call graph
1057 /// must be up-to-date prior to calling this. That means it is by itself in
1058 /// a maximal SCC which is by itself in a maximal RefSCC, etc. No structural
1059 /// changes result from calling this routine other than potentially removing
1060 /// entry points into the call graph.
1061 ///
1062 /// If SCC formation has begun, this function must not be part of the current
1063 /// DFS in order to call this safely. Typically, the function will have been
1064 /// fully visited by the DFS prior to calling this routine.
1066
1067 /// Add a new function split/outlined from an existing function.
1068 ///
1069 /// The new function may only reference other functions that the original
1070 /// function did.
1071 ///
1072 /// The original function must reference (either directly or indirectly) the
1073 /// new function.
1074 ///
1075 /// The new function may also reference the original function.
1076 /// It may end up in a parent SCC in the case that the original function's
1077 /// edge to the new function is a ref edge, and the edge back is a call edge.
1078 void addSplitFunction(Function &OriginalFunction, Function &NewFunction);
1079
1080 /// Add new ref-recursive functions split/outlined from an existing function.
1081 ///
1082 /// The new functions may only reference other functions that the original
1083 /// function did. The new functions may reference (not call) the original
1084 /// function.
1085 ///
1086 /// The original function must reference (not call) all new functions.
1087 /// All new functions must reference (not call) each other.
1088 void addSplitRefRecursiveFunctions(Function &OriginalFunction,
1089 ArrayRef<Function *> NewFunctions);
1090
1091 ///@}
1092
1093 ///@{
1094 /// \name Static helpers for code doing updates to the call graph.
1095 ///
1096 /// These helpers are used to implement parts of the call graph but are also
1097 /// useful to code doing updates or otherwise wanting to walk the IR in the
1098 /// same patterns as when we build the call graph.
1099
1100 /// Recursively visits the defined functions whose address is reachable from
1101 /// every constant in the \p Worklist.
1102 ///
1103 /// Doesn't recurse through any constants already in the \p Visited set, and
1104 /// updates that set with every constant visited.
1105 ///
1106 /// For each defined function, calls \p Callback with that function.
1107 static void visitReferences(SmallVectorImpl<Constant *> &Worklist,
1109 function_ref<void(Function &)> Callback);
1110
1111 ///@}
1112
1113private:
1114 using node_stack_iterator = SmallVectorImpl<Node *>::reverse_iterator;
1115 using node_stack_range = iterator_range<node_stack_iterator>;
1116
1117 /// Allocator that holds all the call graph nodes.
1119
1120 /// Maps function->node for fast lookup.
1122
1123 /// The entry edges into the graph.
1124 ///
1125 /// These edges are from "external" sources. Put another way, they
1126 /// escape at the module scope.
1127 EdgeSequence EntryEdges;
1128
1129 /// Allocator that holds all the call graph SCCs.
1131
1132 /// Maps Function -> SCC for fast lookup.
1134
1135 /// Allocator that holds all the call graph RefSCCs.
1137
1138 /// The post-order sequence of RefSCCs.
1139 ///
1140 /// This list is lazily formed the first time we walk the graph.
1141 SmallVector<RefSCC *, 16> PostOrderRefSCCs;
1142
1143 /// A map from RefSCC to the index for it in the postorder sequence of
1144 /// RefSCCs.
1145 DenseMap<RefSCC *, int> RefSCCIndices;
1146
1147 /// Defined functions that are also known library functions which the
1148 /// optimizer can reason about and therefore might introduce calls to out of
1149 /// thin air.
1150 SmallSetVector<Function *, 4> LibFunctions;
1151
1152 /// Helper to insert a new function, with an already looked-up entry in
1153 /// the NodeMap.
1154 Node &insertInto(Function &F, Node *&MappedN);
1155
1156 /// Helper to initialize a new node created outside of creating SCCs and add
1157 /// it to the NodeMap if necessary. For example, useful when a function is
1158 /// split.
1159 Node &initNode(Function &F);
1160
1161 /// Helper to update pointers back to the graph object during moves.
1162 void updateGraphPtrs();
1163
1164 /// Allocates an SCC and constructs it using the graph allocator.
1165 ///
1166 /// The arguments are forwarded to the constructor.
1167 template <typename... Ts> SCC *createSCC(Ts &&...Args) {
1168 return new (SCCBPA.Allocate()) SCC(std::forward<Ts>(Args)...);
1169 }
1170
1171 /// Allocates a RefSCC and constructs it using the graph allocator.
1172 ///
1173 /// The arguments are forwarded to the constructor.
1174 template <typename... Ts> RefSCC *createRefSCC(Ts &&...Args) {
1175 return new (RefSCCBPA.Allocate()) RefSCC(std::forward<Ts>(Args)...);
1176 }
1177
1178 /// Common logic for building SCCs from a sequence of roots.
1179 ///
1180 /// This is a very generic implementation of the depth-first walk and SCC
1181 /// formation algorithm. It uses a generic sequence of roots and generic
1182 /// callbacks for each step. This is designed to be used to implement both
1183 /// the RefSCC formation and SCC formation with shared logic.
1184 ///
1185 /// Currently this is a relatively naive implementation of Tarjan's DFS
1186 /// algorithm to form the SCCs.
1187 ///
1188 /// FIXME: We should consider newer variants such as Nuutila.
1189 template <typename RootsT, typename GetBeginT, typename GetEndT,
1190 typename GetNodeT, typename FormSCCCallbackT>
1191 static void buildGenericSCCs(RootsT &&Roots, GetBeginT &&GetBegin,
1192 GetEndT &&GetEnd, GetNodeT &&GetNode,
1193 FormSCCCallbackT &&FormSCC);
1194
1195 /// Build the SCCs for a RefSCC out of a list of nodes.
1196 void buildSCCs(RefSCC &RC, node_stack_range Nodes);
1197
1198 /// Get the index of a RefSCC within the postorder traversal.
1199 ///
1200 /// Requires that this RefSCC is a valid one in the (perhaps partial)
1201 /// postorder traversed part of the graph.
1202 int getRefSCCIndex(RefSCC &RC) {
1203 auto IndexIt = RefSCCIndices.find(&RC);
1204 assert(IndexIt != RefSCCIndices.end() && "RefSCC doesn't have an index!");
1205 assert(PostOrderRefSCCs[IndexIt->second] == &RC &&
1206 "Index does not point back at RC!");
1207 return IndexIt->second;
1208 }
1209};
1210
1211inline LazyCallGraph::Edge::Edge() = default;
1213
1214inline LazyCallGraph::Edge::operator bool() const {
1215 return Value.getPointer() && !Value.getPointer()->isDead();
1216}
1217
1219 assert(*this && "Queried a null edge!");
1220 return Value.getInt();
1221}
1222
1223inline bool LazyCallGraph::Edge::isCall() const {
1224 assert(*this && "Queried a null edge!");
1225 return getKind() == Call;
1226}
1227
1229 assert(*this && "Queried a null edge!");
1230 return *Value.getPointer();
1231}
1232
1234 assert(*this && "Queried a null edge!");
1235 return getNode().getFunction();
1236}
1237
1238// Provide GraphTraits specializations for call graphs.
1239template <> struct GraphTraits<LazyCallGraph::Node *> {
1242
1243 static NodeRef getEntryNode(NodeRef N) { return N; }
1244 static ChildIteratorType child_begin(NodeRef N) { return (*N)->begin(); }
1245 static ChildIteratorType child_end(NodeRef N) { return (*N)->end(); }
1246};
1247template <> struct GraphTraits<LazyCallGraph *> {
1250
1251 static NodeRef getEntryNode(NodeRef N) { return N; }
1252 static ChildIteratorType child_begin(NodeRef N) { return (*N)->begin(); }
1253 static ChildIteratorType child_end(NodeRef N) { return (*N)->end(); }
1254};
1255
1256/// An analysis pass which computes the call graph for a module.
1257class LazyCallGraphAnalysis : public AnalysisInfoMixin<LazyCallGraphAnalysis> {
1259
1260 static AnalysisKey Key;
1261
1262public:
1263 /// Inform generic clients of the result type.
1265
1266 /// Compute the \c LazyCallGraph for the module \c M.
1267 ///
1268 /// This just builds the set of entry points to the call graph. The rest is
1269 /// built lazily as it is walked.
1273 auto GetTLI = [&FAM](Function &F) -> TargetLibraryInfo & {
1274 return FAM.getResult<TargetLibraryAnalysis>(F);
1275 };
1276 return LazyCallGraph(M, GetTLI);
1277 }
1278};
1279
1280/// A pass which prints the call graph to a \c raw_ostream.
1281///
1282/// This is primarily useful for testing the analysis.
1284 : public PassInfoMixin<LazyCallGraphPrinterPass> {
1285 raw_ostream &OS;
1286
1287public:
1289
1291};
1292
1293/// A pass which prints the call graph as a DOT file to a \c raw_ostream.
1294///
1295/// This is primarily useful for visualization purposes.
1297 : public PassInfoMixin<LazyCallGraphDOTPrinterPass> {
1298 raw_ostream &OS;
1299
1300public:
1302
1304};
1305
1306} // end namespace llvm
1307
1308#endif // LLVM_ANALYSIS_LAZYCALLGRAPH_H
amdgpu Simplify well known AMD library false FunctionCallee Value * Arg
This file defines the BumpPtrAllocator interface.
static GCRegistry::Add< ShadowStackGC > C("shadow-stack", "Very portable GC for uncooperative code generators")
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
#define LLVM_EXTERNAL_VISIBILITY
Definition: Compiler.h:127
static void clear(coro::Shape &Shape)
Definition: Coroutines.cpp:149
Returns the sub type a function will return at a given Idx Should correspond to the result type of an ExtractValue instruction executed with just that one unsigned Idx
This file defines the DenseMap class.
std::string Name
#define F(x, y, z)
Definition: MD5.cpp:55
#define I(x, y, z)
Definition: MD5.cpp:58
#define G(x, y, z)
Definition: MD5.cpp:56
Machine Check Debug Module
ppc ctr loops verify
FunctionAnalysisManager FAM
This header defines various interfaces for pass management in LLVM.
This file defines the PointerIntPair class.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This file implements a set that has insertion order iteration characteristics.
This file defines the SmallVector class.
Value * RHS
API to communicate dependencies between analyses during invalidation.
Definition: PassManager.h:661
A container for analyses that lazily runs them and caches their results.
Definition: PassManager.h:620
PassT::Result & getResult(IRUnitT &IR, ExtraArgTs... ExtraArgs)
Get the result of an analysis pass for a given IR unit.
Definition: PassManager.h:774
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
iterator find(const_arg_type_t< KeyT > Val)
Definition: DenseMap.h:150
iterator end()
Definition: DenseMap.h:84
An analysis over an "outer" IR unit that provides access to an analysis manager over an "inner" IR un...
Definition: PassManager.h:933
An analysis pass which computes the call graph for a module.
LazyCallGraph run(Module &M, ModuleAnalysisManager &AM)
Compute the LazyCallGraph for the module M.
A pass which prints the call graph as a DOT file to a raw_ostream.
A pass which prints the call graph to a raw_ostream.
An iterator over specifically call edges.
An iterator used for the edges to both entry nodes and child nodes.
The edge sequence object.
iterator_range< call_iterator > calls()
A class used to represent edges in the call graph.
Function & getFunction() const
Get the function referenced by this edge.
bool isCall() const
Test whether the edge represents a direct call to a function.
Kind
The kind of edge in the graph.
Kind getKind() const
Returns the Kind of the edge.
Node & getNode() const
Get the call graph node referenced by this edge.
A node in the call graph.
LazyCallGraph & getGraph() const
EdgeSequence & populate()
Populate the edges of this node if necessary.
bool isDead() const
Tests whether this is actually a dead node and no longer valid.
bool operator!=(const Node &N) const
bool isPopulated() const
Tests whether the node has been populated with edges.
bool operator==(const Node &N) const
Equality is defined as address equality.
friend raw_ostream & operator<<(raw_ostream &OS, const Node &N)
Print the name of this node's function.
EdgeSequence * operator->() const
StringRef getName() const
EdgeSequence & operator*() const
Function & getFunction() const
A RefSCC of the call graph.
SmallVector< RefSCC *, 1 > insertIncomingRefEdge(Node &SourceN, Node &TargetN)
Insert an edge whose source is in a descendant RefSCC and target is in this RefSCC.
bool switchInternalEdgeToCall(Node &SourceN, Node &TargetN, function_ref< void(ArrayRef< SCC * > MergedSCCs)> MergeCB={})
Make an existing internal ref edge into a call edge.
bool isAncestorOf(const RefSCC &RC) const
Test if this RefSCC is an ancestor of RC.
void insertTrivialRefEdge(Node &SourceN, Node &TargetN)
A convenience wrapper around the above to handle trivial cases of inserting a new ref edge.
iterator find(SCC &C) const
bool isDescendantOf(const RefSCC &RC) const
Test if this RefSCC is a descendant of RC.
bool isChildOf(const RefSCC &RC) const
Test if this RefSCC is a child of RC.
void switchOutgoingEdgeToCall(Node &SourceN, Node &TargetN)
Make an existing outgoing ref edge into a call edge.
void replaceNodeFunction(Node &N, Function &NewF)
Directly replace a node's function with a new function.
void insertOutgoingEdge(Node &SourceN, Node &TargetN, Edge::Kind EK)
Insert an edge whose parent is in this RefSCC and child is in some child RefSCC.
SmallVector< RefSCC *, 1 > removeInternalRefEdge(Node &SourceN, ArrayRef< Node * > TargetNs)
Remove a list of ref edges which are entirely within this RefSCC.
iterator_range< iterator > switchInternalEdgeToRef(Node &SourceN, Node &TargetN)
Make an existing internal call edge within a single SCC into a ref edge.
void insertInternalRefEdge(Node &SourceN, Node &TargetN)
Insert a ref edge from one node in this RefSCC to another in this RefSCC.
void insertTrivialCallEdge(Node &SourceN, Node &TargetN)
A convenience wrapper around the above to handle trivial cases of inserting a new call edge.
void removeOutgoingEdge(Node &SourceN, Node &TargetN)
Remove an edge whose source is in this RefSCC and target is not.
std::string getName() const
Provide a short name by printing this RefSCC to a std::string.
void switchOutgoingEdgeToRef(Node &SourceN, Node &TargetN)
Make an existing outgoing call edge into a ref edge.
friend raw_ostream & operator<<(raw_ostream &OS, const RefSCC &RC)
Print a short description useful for debugging or logging.
void switchTrivialInternalEdgeToRef(Node &SourceN, Node &TargetN)
Make an existing internal call edge between separate SCCs into a ref edge.
bool isParentOf(const RefSCC &RC) const
Test if this RefSCC is a parent of RC.
An SCC of the call graph.
iterator end() const
bool isChildOf(const SCC &C) const
Test if this SCC is a child of C.
friend raw_ostream & operator<<(raw_ostream &OS, const SCC &C)
Print a short description useful for debugging or logging.
bool isDescendantOf(const SCC &C) const
Test if this SCC is a descendant of C.
std::string getName() const
Provide a short name by printing this SCC to a std::string.
iterator begin() const
RefSCC & getOuterRefSCC() const
A post-order depth-first RefSCC iterator over the call graph.
postorder_ref_scc_iterator & operator++()
bool operator==(const postorder_ref_scc_iterator &Arg) const
A lazily constructed view of the call graph of a module.
bool isLibFunction(Function &F) const
Test whether a function is a known and defined library function tracked by the call graph.
EdgeSequence::iterator begin()
RefSCC * lookupRefSCC(Node &N) const
Lookup a function's RefSCC in the graph.
void insertEdge(Node &SourceN, Node &TargetN, Edge::Kind EK)
Update the call graph after inserting a new edge.
static void visitReferences(SmallVectorImpl< Constant * > &Worklist, SmallPtrSetImpl< Constant * > &Visited, function_ref< void(Function &)> Callback)
Recursively visits the defined functions whose address is reachable from every constant in the Workli...
void removeDeadFunction(Function &F)
Remove a dead function from the call graph (typically to delete it).
void addSplitFunction(Function &OriginalFunction, Function &NewFunction)
Add a new function split/outlined from an existing function.
void addSplitRefRecursiveFunctions(Function &OriginalFunction, ArrayRef< Function * > NewFunctions)
Add new ref-recursive functions split/outlined from an existing function.
postorder_ref_scc_iterator postorder_ref_scc_begin()
ArrayRef< Function * > getLibFunctions() const
Get the sequence of known and defined library functions.
postorder_ref_scc_iterator postorder_ref_scc_end()
void removeEdge(Node &SourceN, Node &TargetN)
Update the call graph after deleting an edge.
void removeEdge(Function &Source, Function &Target)
Update the call graph after deleting an edge.
void insertEdge(Function &Source, Function &Target, Edge::Kind EK)
Update the call graph after inserting a new edge.
Node & get(Function &F)
Get a graph node for a given function, scanning it to populate the graph data as necessary.
SCC * lookupSCC(Node &N) const
Lookup a function's SCC in the graph.
iterator_range< postorder_ref_scc_iterator > postorder_ref_sccs()
LazyCallGraph & operator=(LazyCallGraph &&RHS)
bool invalidate(Module &, const PreservedAnalyses &PA, ModuleAnalysisManager::Invalidator &)
EdgeSequence::iterator end()
Node * lookup(const Function &F) const
Lookup a function in the graph which has already been scanned and added.
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
PointerIntPair - This class implements a pair of a pointer and small integer.
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:152
A templated base class for SmallPtrSet which provides the typesafe interface that is common across al...
Definition: SmallPtrSet.h:344
A SetVector that performs no allocations if smaller than a certain size.
Definition: SetVector.h:301
size_t size() const
Definition: SmallVector.h:91
typename SuperClass::iterator iterator
Definition: SmallVector.h:581
std::reverse_iterator< iterator > reverse_iterator
Definition: SmallVector.h:258
A BumpPtrAllocator that allows only elements of a specific type to be allocated.
Definition: Allocator.h:382
T * Allocate(size_t num=1)
Allocate space for an array of objects without constructing them.
Definition: Allocator.h:432
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
Analysis pass providing the TargetLibraryInfo.
Provides information about what library functions are available for the current target.
Target - Wrapper for Target specific information.
LLVM Value Representation.
Definition: Value.h:74
An efficient, type-erasing, non-owning reference to a callable.
CRTP base class for adapting an iterator to a different type.
Definition: iterator.h:237
CRTP base class which implements the entire standard iterator facade in terms of a minimal subset of ...
Definition: iterator.h:80
A range adaptor for a pair of iterators.
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
A raw_ostream that writes to an std::string.
Definition: raw_ostream.h:642
This provides a very simple, boring adaptor for a begin and end iterator into a range type.
@ C
The default llvm calling convention, compatible with C.
Definition: CallingConv.h:34
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
void dump(const SparseBitVector< ElementSize > &LHS, raw_ostream &out)
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
Definition: BitVector.h:851
#define N
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:394
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:69
static ChildIteratorType child_begin(NodeRef N)
static ChildIteratorType child_end(NodeRef N)
static NodeRef getEntryNode(NodeRef N)
static ChildIteratorType child_end(NodeRef N)
static ChildIteratorType child_begin(NodeRef N)
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:371
An iterator type that allows iterating over the pointees via some other iterator.
Definition: iterator.h:324