1 //===- llvm/ModuleSummaryIndex.h - Module Summary Index ---------*- C++ -*-===//
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
7 //===----------------------------------------------------------------------===//
10 /// ModuleSummaryIndex.h This file contains the declarations the classes that
11 /// hold the module index and summary for function importing.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_IR_MODULESUMMARYINDEX_H
16 #define LLVM_IR_MODULESUMMARYINDEX_H
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ADT/SmallString.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/ADT/StringMap.h"
24 #include "llvm/ADT/StringRef.h"
25 #include "llvm/ADT/TinyPtrVector.h"
26 #include "llvm/IR/GlobalValue.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/Support/Allocator.h"
29 #include "llvm/Support/MathExtras.h"
30 #include "llvm/Support/ScaledNumber.h"
31 #include "llvm/Support/StringSaver.h"
48 template <typename T> struct MappingTraits;
50 } // end namespace yaml
52 /// Class to accumulate and hold information about a callee.
54 enum class HotnessType : uint8_t {
62 // The size of the bit-field might need to be adjusted if more values are
63 // added to HotnessType enum.
66 /// The value stored in RelBlockFreq has to be interpreted as the digits of
67 /// a scaled number with a scale of \p -ScaleShift.
68 uint32_t RelBlockFreq : 29;
69 static constexpr int32_t ScaleShift = 8;
70 static constexpr uint64_t MaxRelBlockFreq = (1 << 29) - 1;
73 : Hotness(static_cast<uint32_t>(HotnessType::Unknown)), RelBlockFreq(0) {}
74 explicit CalleeInfo(HotnessType Hotness, uint64_t RelBF)
75 : Hotness(static_cast<uint32_t>(Hotness)), RelBlockFreq(RelBF) {}
77 void updateHotness(const HotnessType OtherHotness) {
78 Hotness = std::max(Hotness, static_cast<uint32_t>(OtherHotness));
81 HotnessType getHotness() const { return HotnessType(Hotness); }
83 /// Update \p RelBlockFreq from \p BlockFreq and \p EntryFreq
85 /// BlockFreq is divided by EntryFreq and added to RelBlockFreq. To represent
86 /// fractional values, the result is represented as a fixed point number with
87 /// scale of -ScaleShift.
88 void updateRelBlockFreq(uint64_t BlockFreq, uint64_t EntryFreq) {
91 using Scaled64 = ScaledNumber<uint64_t>;
92 Scaled64 Temp(BlockFreq, ScaleShift);
93 Temp /= Scaled64::get(EntryFreq);
96 SaturatingAdd<uint64_t>(Temp.toInt<uint64_t>(), RelBlockFreq);
97 Sum = std::min(Sum, uint64_t(MaxRelBlockFreq));
98 RelBlockFreq = static_cast<uint32_t>(Sum);
102 inline const char *getHotnessName(CalleeInfo::HotnessType HT) {
104 case CalleeInfo::HotnessType::Unknown:
106 case CalleeInfo::HotnessType::Cold:
108 case CalleeInfo::HotnessType::None:
110 case CalleeInfo::HotnessType::Hot:
112 case CalleeInfo::HotnessType::Critical:
115 llvm_unreachable("invalid hotness");
118 class GlobalValueSummary;
120 using GlobalValueSummaryList = std::vector<std::unique_ptr<GlobalValueSummary>>;
122 struct GlobalValueSummaryInfo {
124 NameOrGV(bool HaveGVs) {
131 /// The GlobalValue corresponding to this summary. This is only used in
132 /// per-module summaries and when the IR is available. E.g. when module
133 /// analysis is being run, or when parsing both the IR and the summary
135 const GlobalValue *GV;
137 /// Summary string representation. This StringRef points to BC module
138 /// string table and is valid until module data is stored in memory.
139 /// This is guaranteed to happen until runThinLTOBackend function is
140 /// called, so it is safe to use this field during thin link. This field
141 /// is only valid if summary index was loaded from BC file.
145 GlobalValueSummaryInfo(bool HaveGVs) : U(HaveGVs) {}
147 /// List of global value summary structures for a particular value held
148 /// in the GlobalValueMap. Requires a vector in the case of multiple
149 /// COMDAT values of the same name.
150 GlobalValueSummaryList SummaryList;
153 /// Map from global value GUID to corresponding summary structures. Use a
154 /// std::map rather than a DenseMap so that pointers to the map's value_type
155 /// (which are used by ValueInfo) are not invalidated by insertion. Also it will
156 /// likely incur less overhead, as the value type is not very small and the size
157 /// of the map is unknown, resulting in inefficiencies due to repeated
158 /// insertions and resizing.
159 using GlobalValueSummaryMapTy =
160 std::map<GlobalValue::GUID, GlobalValueSummaryInfo>;
162 /// Struct that holds a reference to a particular GUID in a global value
165 PointerIntPair<const GlobalValueSummaryMapTy::value_type *, 2, int>
168 ValueInfo() = default;
169 ValueInfo(bool HaveGVs, const GlobalValueSummaryMapTy::value_type *R) {
170 RefAndFlags.setPointer(R);
171 RefAndFlags.setInt(HaveGVs);
174 operator bool() const { return getRef(); }
176 GlobalValue::GUID getGUID() const { return getRef()->first; }
177 const GlobalValue *getValue() const {
179 return getRef()->second.U.GV;
182 ArrayRef<std::unique_ptr<GlobalValueSummary>> getSummaryList() const {
183 return getRef()->second.SummaryList;
186 StringRef name() const {
187 return haveGVs() ? getRef()->second.U.GV->getName()
188 : getRef()->second.U.Name;
191 bool haveGVs() const { return RefAndFlags.getInt() & 0x1; }
192 bool isReadOnly() const { return RefAndFlags.getInt() & 0x2; }
193 void setReadOnly() { RefAndFlags.setInt(RefAndFlags.getInt() | 0x2); }
195 const GlobalValueSummaryMapTy::value_type *getRef() const {
196 return RefAndFlags.getPointer();
199 bool isDSOLocal() const;
201 /// Checks if all copies are eligible for auto-hiding (have flag set).
202 bool canAutoHide() const;
205 inline raw_ostream &operator<<(raw_ostream &OS, const ValueInfo &VI) {
207 if (!VI.name().empty())
208 OS << " (" << VI.name() << ")";
212 inline bool operator==(const ValueInfo &A, const ValueInfo &B) {
213 assert(A.getRef() && B.getRef() &&
214 "Need ValueInfo with non-null Ref for comparison");
215 return A.getRef() == B.getRef();
218 inline bool operator!=(const ValueInfo &A, const ValueInfo &B) {
219 assert(A.getRef() && B.getRef() &&
220 "Need ValueInfo with non-null Ref for comparison");
221 return A.getRef() != B.getRef();
224 inline bool operator<(const ValueInfo &A, const ValueInfo &B) {
225 assert(A.getRef() && B.getRef() &&
226 "Need ValueInfo with non-null Ref to compare GUIDs");
227 return A.getGUID() < B.getGUID();
230 template <> struct DenseMapInfo<ValueInfo> {
231 static inline ValueInfo getEmptyKey() {
232 return ValueInfo(false, (GlobalValueSummaryMapTy::value_type *)-8);
235 static inline ValueInfo getTombstoneKey() {
236 return ValueInfo(false, (GlobalValueSummaryMapTy::value_type *)-16);
239 static inline bool isSpecialKey(ValueInfo V) {
240 return V == getTombstoneKey() || V == getEmptyKey();
243 static bool isEqual(ValueInfo L, ValueInfo R) {
244 // We are not supposed to mix ValueInfo(s) with different HaveGVs flag
245 // in a same container.
246 assert(isSpecialKey(L) || isSpecialKey(R) || (L.haveGVs() == R.haveGVs()));
247 return L.getRef() == R.getRef();
249 static unsigned getHashValue(ValueInfo I) { return (uintptr_t)I.getRef(); }
252 /// Function and variable summary information to aid decisions and
253 /// implementation of importing.
254 class GlobalValueSummary {
256 /// Sububclass discriminator (for dyn_cast<> et al.)
257 enum SummaryKind : unsigned { AliasKind, FunctionKind, GlobalVarKind };
259 /// Group flags (Linkage, NotEligibleToImport, etc.) as a bitfield.
261 /// The linkage type of the associated global value.
263 /// One use is to flag values that have local linkage types and need to
264 /// have module identifier appended before placing into the combined
265 /// index, to disambiguate from other values with the same name.
266 /// In the future this will be used to update and optimize linkage
267 /// types based on global summary-based analysis.
268 unsigned Linkage : 4;
270 /// Indicate if the global value cannot be imported (e.g. it cannot
271 /// be renamed or references something that can't be renamed).
272 unsigned NotEligibleToImport : 1;
274 /// In per-module summary, indicate that the global value must be considered
275 /// a live root for index-based liveness analysis. Used for special LLVM
276 /// values such as llvm.global_ctors that the linker does not know about.
278 /// In combined summary, indicate that the global value is live.
281 /// Indicates that the linker resolved the symbol to a definition from
282 /// within the same linkage unit.
283 unsigned DSOLocal : 1;
285 /// In the per-module summary, indicates that the global value is
286 /// linkonce_odr and global unnamed addr (so eligible for auto-hiding
287 /// via hidden visibility). In the combined summary, indicates that the
288 /// prevailing linkonce_odr copy can be auto-hidden via hidden visibility
289 /// when it is upgraded to weak_odr in the backend. This is legal when
290 /// all copies are eligible for auto-hiding (i.e. all copies were
291 /// linkonce_odr global unnamed addr. If any copy is not (e.g. it was
292 /// originally weak_odr, we cannot auto-hide the prevailing copy as it
293 /// means the symbol was externally visible.
294 unsigned CanAutoHide : 1;
296 /// Convenience Constructors
297 explicit GVFlags(GlobalValue::LinkageTypes Linkage,
298 bool NotEligibleToImport, bool Live, bool IsLocal,
300 : Linkage(Linkage), NotEligibleToImport(NotEligibleToImport),
301 Live(Live), DSOLocal(IsLocal), CanAutoHide(CanAutoHide) {}
305 /// Kind of summary for use in dyn_cast<> et al.
310 /// This is the hash of the name of the symbol in the original file. It is
311 /// identical to the GUID for global symbols, but differs for local since the
312 /// GUID includes the module level id in the hash.
313 GlobalValue::GUID OriginalName = 0;
315 /// Path of module IR containing value's definition, used to locate
316 /// module during importing.
318 /// This is only used during parsing of the combined index, or when
319 /// parsing the per-module index for creation of the combined summary index,
320 /// not during writing of the per-module index which doesn't contain a
321 /// module path string table.
322 StringRef ModulePath;
324 /// List of values referenced by this global value's definition
325 /// (either by the initializer of a global variable, or referenced
326 /// from within a function). This does not include functions called, which
327 /// are listed in the derived FunctionSummary object.
328 std::vector<ValueInfo> RefEdgeList;
331 GlobalValueSummary(SummaryKind K, GVFlags Flags, std::vector<ValueInfo> Refs)
332 : Kind(K), Flags(Flags), RefEdgeList(std::move(Refs)) {
333 assert((K != AliasKind || Refs.empty()) &&
334 "Expect no references for AliasSummary");
338 virtual ~GlobalValueSummary() = default;
340 /// Returns the hash of the original name, it is identical to the GUID for
341 /// externally visible symbols, but not for local ones.
342 GlobalValue::GUID getOriginalName() const { return OriginalName; }
344 /// Initialize the original name hash in this summary.
345 void setOriginalName(GlobalValue::GUID Name) { OriginalName = Name; }
347 /// Which kind of summary subclass this is.
348 SummaryKind getSummaryKind() const { return Kind; }
350 /// Set the path to the module containing this function, for use in
351 /// the combined index.
352 void setModulePath(StringRef ModPath) { ModulePath = ModPath; }
354 /// Get the path to the module containing this function.
355 StringRef modulePath() const { return ModulePath; }
357 /// Get the flags for this GlobalValue (see \p struct GVFlags).
358 GVFlags flags() const { return Flags; }
360 /// Return linkage type recorded for this global value.
361 GlobalValue::LinkageTypes linkage() const {
362 return static_cast<GlobalValue::LinkageTypes>(Flags.Linkage);
365 /// Sets the linkage to the value determined by global summary-based
366 /// optimization. Will be applied in the ThinLTO backends.
367 void setLinkage(GlobalValue::LinkageTypes Linkage) {
368 Flags.Linkage = Linkage;
371 /// Return true if this global value can't be imported.
372 bool notEligibleToImport() const { return Flags.NotEligibleToImport; }
374 bool isLive() const { return Flags.Live; }
376 void setLive(bool Live) { Flags.Live = Live; }
378 void setDSOLocal(bool Local) { Flags.DSOLocal = Local; }
380 bool isDSOLocal() const { return Flags.DSOLocal; }
382 void setCanAutoHide(bool CanAutoHide) { Flags.CanAutoHide = CanAutoHide; }
384 bool canAutoHide() const { return Flags.CanAutoHide; }
386 /// Flag that this global value cannot be imported.
387 void setNotEligibleToImport() { Flags.NotEligibleToImport = true; }
389 /// Return the list of values referenced by this global value definition.
390 ArrayRef<ValueInfo> refs() const { return RefEdgeList; }
392 /// If this is an alias summary, returns the summary of the aliased object (a
393 /// global variable or function), otherwise returns itself.
394 GlobalValueSummary *getBaseObject();
395 const GlobalValueSummary *getBaseObject() const;
397 friend class ModuleSummaryIndex;
400 /// Alias summary information.
401 class AliasSummary : public GlobalValueSummary {
402 ValueInfo AliaseeValueInfo;
404 /// This is the Aliasee in the same module as alias (could get from VI, trades
405 /// memory for time). Note that this pointer may be null (and the value info
406 /// empty) when we have a distributed index where the alias is being imported
407 /// (as a copy of the aliasee), but the aliasee is not.
408 GlobalValueSummary *AliaseeSummary;
411 AliasSummary(GVFlags Flags)
412 : GlobalValueSummary(AliasKind, Flags, ArrayRef<ValueInfo>{}),
413 AliaseeSummary(nullptr) {}
415 /// Check if this is an alias summary.
416 static bool classof(const GlobalValueSummary *GVS) {
417 return GVS->getSummaryKind() == AliasKind;
420 void setAliasee(ValueInfo &AliaseeVI, GlobalValueSummary *Aliasee) {
421 AliaseeValueInfo = AliaseeVI;
422 AliaseeSummary = Aliasee;
425 bool hasAliasee() const {
426 assert(!!AliaseeSummary == (AliaseeValueInfo &&
427 !AliaseeValueInfo.getSummaryList().empty()) &&
428 "Expect to have both aliasee summary and summary list or neither");
429 return !!AliaseeSummary;
432 const GlobalValueSummary &getAliasee() const {
433 assert(AliaseeSummary && "Unexpected missing aliasee summary");
434 return *AliaseeSummary;
437 GlobalValueSummary &getAliasee() {
438 return const_cast<GlobalValueSummary &>(
439 static_cast<const AliasSummary *>(this)->getAliasee());
441 ValueInfo getAliaseeVI() const {
442 assert(AliaseeValueInfo && "Unexpected missing aliasee");
443 return AliaseeValueInfo;
445 GlobalValue::GUID getAliaseeGUID() const {
446 assert(AliaseeValueInfo && "Unexpected missing aliasee");
447 return AliaseeValueInfo.getGUID();
451 const inline GlobalValueSummary *GlobalValueSummary::getBaseObject() const {
452 if (auto *AS = dyn_cast<AliasSummary>(this))
453 return &AS->getAliasee();
457 inline GlobalValueSummary *GlobalValueSummary::getBaseObject() {
458 if (auto *AS = dyn_cast<AliasSummary>(this))
459 return &AS->getAliasee();
463 /// Function summary information to aid decisions and implementation of
465 class FunctionSummary : public GlobalValueSummary {
467 /// <CalleeValueInfo, CalleeInfo> call edge pair.
468 using EdgeTy = std::pair<ValueInfo, CalleeInfo>;
470 /// Types for -force-summary-edges-cold debugging option.
471 enum ForceSummaryHotnessType : unsigned {
477 /// An "identifier" for a virtual function. This contains the type identifier
478 /// represented as a GUID and the offset from the address point to the virtual
479 /// function pointer, where "address point" is as defined in the Itanium ABI:
480 /// https://itanium-cxx-abi.github.io/cxx-abi/abi.html#vtable-general
482 GlobalValue::GUID GUID;
486 /// A specification for a virtual function call with all constant integer
487 /// arguments. This is used to perform virtual constant propagation on the
491 std::vector<uint64_t> Args;
494 /// All type identifier related information. Because these fields are
495 /// relatively uncommon we only allocate space for them if necessary.
497 /// List of type identifiers used by this function in llvm.type.test
498 /// intrinsics referenced by something other than an llvm.assume intrinsic,
499 /// represented as GUIDs.
500 std::vector<GlobalValue::GUID> TypeTests;
502 /// List of virtual calls made by this function using (respectively)
503 /// llvm.assume(llvm.type.test) or llvm.type.checked.load intrinsics that do
504 /// not have all constant integer arguments.
505 std::vector<VFuncId> TypeTestAssumeVCalls, TypeCheckedLoadVCalls;
507 /// List of virtual calls made by this function using (respectively)
508 /// llvm.assume(llvm.type.test) or llvm.type.checked.load intrinsics with
509 /// all constant integer arguments.
510 std::vector<ConstVCall> TypeTestAssumeConstVCalls,
511 TypeCheckedLoadConstVCalls;
514 /// Flags specific to function summaries.
516 // Function attribute flags. Used to track if a function accesses memory,
517 // recurses or aliases.
518 unsigned ReadNone : 1;
519 unsigned ReadOnly : 1;
520 unsigned NoRecurse : 1;
521 unsigned ReturnDoesNotAlias : 1;
523 // Indicate if the global value cannot be inlined.
524 unsigned NoInline : 1;
527 /// Create an empty FunctionSummary (with specified call edges).
528 /// Used to represent external nodes and the dummy root node.
529 static FunctionSummary
530 makeDummyFunctionSummary(std::vector<FunctionSummary::EdgeTy> Edges) {
531 return FunctionSummary(
532 FunctionSummary::GVFlags(
533 GlobalValue::LinkageTypes::AvailableExternallyLinkage,
534 /*NotEligibleToImport=*/true, /*Live=*/true, /*IsLocal=*/false,
535 /*CanAutoHide=*/false),
536 /*InsCount=*/0, FunctionSummary::FFlags{}, /*EntryCount=*/0,
537 std::vector<ValueInfo>(), std::move(Edges),
538 std::vector<GlobalValue::GUID>(),
539 std::vector<FunctionSummary::VFuncId>(),
540 std::vector<FunctionSummary::VFuncId>(),
541 std::vector<FunctionSummary::ConstVCall>(),
542 std::vector<FunctionSummary::ConstVCall>());
545 /// A dummy node to reference external functions that aren't in the index
546 static FunctionSummary ExternalNode;
549 /// Number of instructions (ignoring debug instructions, e.g.) computed
550 /// during the initial compile step when the summary index is first built.
553 /// Function summary specific flags.
556 /// The synthesized entry count of the function.
557 /// This is only populated during ThinLink phase and remains unused while
558 /// generating per-module summaries.
559 uint64_t EntryCount = 0;
561 /// List of <CalleeValueInfo, CalleeInfo> call edge pairs from this function.
562 std::vector<EdgeTy> CallGraphEdgeList;
564 std::unique_ptr<TypeIdInfo> TIdInfo;
567 FunctionSummary(GVFlags Flags, unsigned NumInsts, FFlags FunFlags,
568 uint64_t EntryCount, std::vector<ValueInfo> Refs,
569 std::vector<EdgeTy> CGEdges,
570 std::vector<GlobalValue::GUID> TypeTests,
571 std::vector<VFuncId> TypeTestAssumeVCalls,
572 std::vector<VFuncId> TypeCheckedLoadVCalls,
573 std::vector<ConstVCall> TypeTestAssumeConstVCalls,
574 std::vector<ConstVCall> TypeCheckedLoadConstVCalls)
575 : GlobalValueSummary(FunctionKind, Flags, std::move(Refs)),
576 InstCount(NumInsts), FunFlags(FunFlags), EntryCount(EntryCount),
577 CallGraphEdgeList(std::move(CGEdges)) {
578 if (!TypeTests.empty() || !TypeTestAssumeVCalls.empty() ||
579 !TypeCheckedLoadVCalls.empty() || !TypeTestAssumeConstVCalls.empty() ||
580 !TypeCheckedLoadConstVCalls.empty())
581 TIdInfo = llvm::make_unique<TypeIdInfo>(TypeIdInfo{
582 std::move(TypeTests), std::move(TypeTestAssumeVCalls),
583 std::move(TypeCheckedLoadVCalls),
584 std::move(TypeTestAssumeConstVCalls),
585 std::move(TypeCheckedLoadConstVCalls)});
587 // Gets the number of immutable refs in RefEdgeList
588 unsigned immutableRefCount() const;
590 /// Check if this is a function summary.
591 static bool classof(const GlobalValueSummary *GVS) {
592 return GVS->getSummaryKind() == FunctionKind;
595 /// Get function summary flags.
596 FFlags fflags() const { return FunFlags; }
598 /// Get the instruction count recorded for this function.
599 unsigned instCount() const { return InstCount; }
601 /// Get the synthetic entry count for this function.
602 uint64_t entryCount() const { return EntryCount; }
604 /// Set the synthetic entry count for this function.
605 void setEntryCount(uint64_t EC) { EntryCount = EC; }
607 /// Return the list of <CalleeValueInfo, CalleeInfo> pairs.
608 ArrayRef<EdgeTy> calls() const { return CallGraphEdgeList; }
610 /// Returns the list of type identifiers used by this function in
611 /// llvm.type.test intrinsics other than by an llvm.assume intrinsic,
612 /// represented as GUIDs.
613 ArrayRef<GlobalValue::GUID> type_tests() const {
615 return TIdInfo->TypeTests;
619 /// Returns the list of virtual calls made by this function using
620 /// llvm.assume(llvm.type.test) intrinsics that do not have all constant
621 /// integer arguments.
622 ArrayRef<VFuncId> type_test_assume_vcalls() const {
624 return TIdInfo->TypeTestAssumeVCalls;
628 /// Returns the list of virtual calls made by this function using
629 /// llvm.type.checked.load intrinsics that do not have all constant integer
631 ArrayRef<VFuncId> type_checked_load_vcalls() const {
633 return TIdInfo->TypeCheckedLoadVCalls;
637 /// Returns the list of virtual calls made by this function using
638 /// llvm.assume(llvm.type.test) intrinsics with all constant integer
640 ArrayRef<ConstVCall> type_test_assume_const_vcalls() const {
642 return TIdInfo->TypeTestAssumeConstVCalls;
646 /// Returns the list of virtual calls made by this function using
647 /// llvm.type.checked.load intrinsics with all constant integer arguments.
648 ArrayRef<ConstVCall> type_checked_load_const_vcalls() const {
650 return TIdInfo->TypeCheckedLoadConstVCalls;
654 /// Add a type test to the summary. This is used by WholeProgramDevirt if we
655 /// were unable to devirtualize a checked call.
656 void addTypeTest(GlobalValue::GUID Guid) {
658 TIdInfo = llvm::make_unique<TypeIdInfo>();
659 TIdInfo->TypeTests.push_back(Guid);
662 const TypeIdInfo *getTypeIdInfo() const { return TIdInfo.get(); };
664 friend struct GraphTraits<ValueInfo>;
667 template <> struct DenseMapInfo<FunctionSummary::VFuncId> {
668 static FunctionSummary::VFuncId getEmptyKey() { return {0, uint64_t(-1)}; }
670 static FunctionSummary::VFuncId getTombstoneKey() {
671 return {0, uint64_t(-2)};
674 static bool isEqual(FunctionSummary::VFuncId L, FunctionSummary::VFuncId R) {
675 return L.GUID == R.GUID && L.Offset == R.Offset;
678 static unsigned getHashValue(FunctionSummary::VFuncId I) { return I.GUID; }
681 template <> struct DenseMapInfo<FunctionSummary::ConstVCall> {
682 static FunctionSummary::ConstVCall getEmptyKey() {
683 return {{0, uint64_t(-1)}, {}};
686 static FunctionSummary::ConstVCall getTombstoneKey() {
687 return {{0, uint64_t(-2)}, {}};
690 static bool isEqual(FunctionSummary::ConstVCall L,
691 FunctionSummary::ConstVCall R) {
692 return DenseMapInfo<FunctionSummary::VFuncId>::isEqual(L.VFunc, R.VFunc) &&
696 static unsigned getHashValue(FunctionSummary::ConstVCall I) {
701 /// Global variable summary information to aid decisions and
702 /// implementation of importing.
704 /// Global variable summary has extra flag, telling if it is
705 /// modified during the program run or not. This affects ThinLTO
707 class GlobalVarSummary : public GlobalValueSummary {
710 GVarFlags(bool ReadOnly = false) : ReadOnly(ReadOnly) {}
712 unsigned ReadOnly : 1;
715 GlobalVarSummary(GVFlags Flags, GVarFlags VarFlags,
716 std::vector<ValueInfo> Refs)
717 : GlobalValueSummary(GlobalVarKind, Flags, std::move(Refs)),
718 VarFlags(VarFlags) {}
720 /// Check if this is a global variable summary.
721 static bool classof(const GlobalValueSummary *GVS) {
722 return GVS->getSummaryKind() == GlobalVarKind;
725 GVarFlags varflags() const { return VarFlags; }
726 void setReadOnly(bool RO) { VarFlags.ReadOnly = RO; }
727 bool isReadOnly() const { return VarFlags.ReadOnly; }
730 struct TypeTestResolution {
731 /// Specifies which kind of type check we should emit for this byte array.
732 /// See http://clang.llvm.org/docs/ControlFlowIntegrityDesign.html for full
733 /// details on each kind of check; the enumerators are described with
734 /// reference to that document.
736 Unsat, ///< Unsatisfiable type (i.e. no global has this type metadata)
737 ByteArray, ///< Test a byte array (first example)
738 Inline, ///< Inlined bit vector ("Short Inline Bit Vectors")
739 Single, ///< Single element (last example in "Short Inline Bit Vectors")
740 AllOnes, ///< All-ones bit vector ("Eliminating Bit Vector Checks for
741 /// All-Ones Bit Vectors")
744 /// Range of size-1 expressed as a bit width. For example, if the size is in
745 /// range [1,256], this number will be 8. This helps generate the most compact
746 /// instruction sequences.
747 unsigned SizeM1BitWidth = 0;
749 // The following fields are only used if the target does not support the use
750 // of absolute symbols to store constants. Their meanings are the same as the
751 // corresponding fields in LowerTypeTestsModule::TypeIdLowering in
752 // LowerTypeTests.cpp.
754 uint64_t AlignLog2 = 0;
757 uint64_t InlineBits = 0;
760 struct WholeProgramDevirtResolution {
762 Indir, ///< Just do a regular virtual call
763 SingleImpl, ///< Single implementation devirtualization
764 BranchFunnel, ///< When retpoline mitigation is enabled, use a branch funnel
765 ///< that is defined in the merged module. Otherwise same as
769 std::string SingleImplName;
773 Indir, ///< Just do a regular virtual call
774 UniformRetVal, ///< Uniform return value optimization
775 UniqueRetVal, ///< Unique return value optimization
776 VirtualConstProp, ///< Virtual constant propagation
779 /// Additional information for the resolution:
780 /// - UniformRetVal: the uniform return value.
781 /// - UniqueRetVal: the return value associated with the unique vtable (0 or
785 // The following fields are only used if the target does not support the use
786 // of absolute symbols to store constants.
792 /// Resolutions for calls with all constant integer arguments (excluding the
793 /// first argument, "this"), where the key is the argument vector.
794 std::map<std::vector<uint64_t>, ByArg> ResByArg;
797 struct TypeIdSummary {
798 TypeTestResolution TTRes;
800 /// Mapping from byte offset to whole-program devirt resolution for that
801 /// (typeid, byte offset) pair.
802 std::map<uint64_t, WholeProgramDevirtResolution> WPDRes;
806 using ModuleHash = std::array<uint32_t, 5>;
808 /// Type used for iterating through the global value summary map.
809 using const_gvsummary_iterator = GlobalValueSummaryMapTy::const_iterator;
810 using gvsummary_iterator = GlobalValueSummaryMapTy::iterator;
812 /// String table to hold/own module path strings, which additionally holds the
813 /// module ID assigned to each module during the plugin step, as well as a hash
814 /// of the module. The StringMap makes a copy of and owns inserted strings.
815 using ModulePathStringTableTy = StringMap<std::pair<uint64_t, ModuleHash>>;
817 /// Map of global value GUID to its summary, used to identify values defined in
818 /// a particular module, and provide efficient access to their summary.
819 using GVSummaryMapTy = DenseMap<GlobalValue::GUID, GlobalValueSummary *>;
821 /// Map of a type GUID to type id string and summary (multimap used
822 /// in case of GUID conflicts).
823 using TypeIdSummaryMapTy =
824 std::multimap<GlobalValue::GUID, std::pair<std::string, TypeIdSummary>>;
826 /// Class to hold module path string table and global value map,
827 /// and encapsulate methods for operating on them.
828 class ModuleSummaryIndex {
830 /// Map from value name to list of summary instances for values of that
831 /// name (may be duplicates in the COMDAT case, e.g.).
832 GlobalValueSummaryMapTy GlobalValueMap;
834 /// Holds strings for combined index, mapping to the corresponding module ID.
835 ModulePathStringTableTy ModulePathStringTable;
837 /// Mapping from type identifier GUIDs to type identifier and its summary
839 TypeIdSummaryMapTy TypeIdMap;
841 /// Mapping from original ID to GUID. If original ID can map to multiple
842 /// GUIDs, it will be mapped to 0.
843 std::map<GlobalValue::GUID, GlobalValue::GUID> OidGuidMap;
845 /// Indicates that summary-based GlobalValue GC has run, and values with
846 /// GVFlags::Live==false are really dead. Otherwise, all values must be
848 bool WithGlobalValueDeadStripping = false;
850 /// Indicates that summary-based synthetic entry count propagation has run
851 bool HasSyntheticEntryCounts = false;
853 /// Indicates that distributed backend should skip compilation of the
854 /// module. Flag is suppose to be set by distributed ThinLTO indexing
855 /// when it detected that the module is not needed during the final
856 /// linking. As result distributed backend should just output a minimal
857 /// valid object file.
858 bool SkipModuleByDistributedBackend = false;
860 /// If true then we're performing analysis of IR module, or parsing along with
861 /// the IR from assembly. The value of 'false' means we're reading summary
862 /// from BC or YAML source. Affects the type of value stored in NameOrGV
866 // True if the index was created for a module compiled with -fsplit-lto-unit.
867 bool EnableSplitLTOUnit;
869 // True if some of the modules were compiled with -fsplit-lto-unit and
870 // some were not. Set when the combined index is created during the thin link.
871 bool PartiallySplitLTOUnits = false;
873 std::set<std::string> CfiFunctionDefs;
874 std::set<std::string> CfiFunctionDecls;
876 // Used in cases where we want to record the name of a global, but
877 // don't have the string owned elsewhere (e.g. the Strtab on a module).
879 BumpPtrAllocator Alloc;
882 friend yaml::MappingTraits<ModuleSummaryIndex>;
884 GlobalValueSummaryMapTy::value_type *
885 getOrInsertValuePtr(GlobalValue::GUID GUID) {
886 return &*GlobalValueMap.emplace(GUID, GlobalValueSummaryInfo(HaveGVs))
891 // See HaveGVs variable comment.
892 ModuleSummaryIndex(bool HaveGVs, bool EnableSplitLTOUnit = false)
893 : HaveGVs(HaveGVs), EnableSplitLTOUnit(EnableSplitLTOUnit), Saver(Alloc) {
896 bool haveGVs() const { return HaveGVs; }
898 gvsummary_iterator begin() { return GlobalValueMap.begin(); }
899 const_gvsummary_iterator begin() const { return GlobalValueMap.begin(); }
900 gvsummary_iterator end() { return GlobalValueMap.end(); }
901 const_gvsummary_iterator end() const { return GlobalValueMap.end(); }
902 size_t size() const { return GlobalValueMap.size(); }
904 /// Convenience function for doing a DFS on a ValueInfo. Marks the function in
905 /// the FunctionHasParent map.
906 static void discoverNodes(ValueInfo V,
907 std::map<ValueInfo, bool> &FunctionHasParent) {
908 if (!V.getSummaryList().size())
909 return; // skip external functions that don't have summaries
911 // Mark discovered if we haven't yet
912 auto S = FunctionHasParent.emplace(V, false);
914 // Stop if we've already discovered this node
919 dyn_cast<FunctionSummary>(V.getSummaryList().front().get());
920 assert(F != nullptr && "Expected FunctionSummary node");
922 for (auto &C : F->calls()) {
923 // Insert node if necessary
924 auto S = FunctionHasParent.emplace(C.first, true);
926 // Skip nodes that we're sure have parents
927 if (!S.second && S.first->second)
931 discoverNodes(C.first, FunctionHasParent);
933 S.first->second = true;
937 // Calculate the callgraph root
938 FunctionSummary calculateCallGraphRoot() {
939 // Functions that have a parent will be marked in FunctionHasParent pair.
940 // Once we've marked all functions, the functions in the map that are false
941 // have no parent (so they're the roots)
942 std::map<ValueInfo, bool> FunctionHasParent;
944 for (auto &S : *this) {
945 // Skip external functions
946 if (!S.second.SummaryList.size() ||
947 !isa<FunctionSummary>(S.second.SummaryList.front().get()))
949 discoverNodes(ValueInfo(HaveGVs, &S), FunctionHasParent);
952 std::vector<FunctionSummary::EdgeTy> Edges;
953 // create edges to all roots in the Index
954 for (auto &P : FunctionHasParent) {
956 continue; // skip over non-root nodes
957 Edges.push_back(std::make_pair(P.first, CalleeInfo{}));
960 // Failed to find root - return an empty node
961 return FunctionSummary::makeDummyFunctionSummary({});
963 auto CallGraphRoot = FunctionSummary::makeDummyFunctionSummary(Edges);
964 return CallGraphRoot;
967 bool withGlobalValueDeadStripping() const {
968 return WithGlobalValueDeadStripping;
970 void setWithGlobalValueDeadStripping() {
971 WithGlobalValueDeadStripping = true;
974 bool hasSyntheticEntryCounts() const { return HasSyntheticEntryCounts; }
975 void setHasSyntheticEntryCounts() { HasSyntheticEntryCounts = true; }
977 bool skipModuleByDistributedBackend() const {
978 return SkipModuleByDistributedBackend;
980 void setSkipModuleByDistributedBackend() {
981 SkipModuleByDistributedBackend = true;
984 bool enableSplitLTOUnit() const { return EnableSplitLTOUnit; }
985 void setEnableSplitLTOUnit() { EnableSplitLTOUnit = true; }
987 bool partiallySplitLTOUnits() const { return PartiallySplitLTOUnits; }
988 void setPartiallySplitLTOUnits() { PartiallySplitLTOUnits = true; }
990 bool isGlobalValueLive(const GlobalValueSummary *GVS) const {
991 return !WithGlobalValueDeadStripping || GVS->isLive();
993 bool isGUIDLive(GlobalValue::GUID GUID) const;
995 /// Return a ValueInfo for the index value_type (convenient when iterating
997 ValueInfo getValueInfo(const GlobalValueSummaryMapTy::value_type &R) const {
998 return ValueInfo(HaveGVs, &R);
1001 /// Return a ValueInfo for GUID if it exists, otherwise return ValueInfo().
1002 ValueInfo getValueInfo(GlobalValue::GUID GUID) const {
1003 auto I = GlobalValueMap.find(GUID);
1004 return ValueInfo(HaveGVs, I == GlobalValueMap.end() ? nullptr : &*I);
1007 /// Return a ValueInfo for \p GUID.
1008 ValueInfo getOrInsertValueInfo(GlobalValue::GUID GUID) {
1009 return ValueInfo(HaveGVs, getOrInsertValuePtr(GUID));
1012 // Save a string in the Index. Use before passing Name to
1013 // getOrInsertValueInfo when the string isn't owned elsewhere (e.g. on the
1014 // module's Strtab).
1015 StringRef saveString(StringRef String) { return Saver.save(String); }
1017 /// Return a ValueInfo for \p GUID setting value \p Name.
1018 ValueInfo getOrInsertValueInfo(GlobalValue::GUID GUID, StringRef Name) {
1020 auto VP = getOrInsertValuePtr(GUID);
1021 VP->second.U.Name = Name;
1022 return ValueInfo(HaveGVs, VP);
1025 /// Return a ValueInfo for \p GV and mark it as belonging to GV.
1026 ValueInfo getOrInsertValueInfo(const GlobalValue *GV) {
1028 auto VP = getOrInsertValuePtr(GV->getGUID());
1029 VP->second.U.GV = GV;
1030 return ValueInfo(HaveGVs, VP);
1033 /// Return the GUID for \p OriginalId in the OidGuidMap.
1034 GlobalValue::GUID getGUIDFromOriginalID(GlobalValue::GUID OriginalID) const {
1035 const auto I = OidGuidMap.find(OriginalID);
1036 return I == OidGuidMap.end() ? 0 : I->second;
1039 std::set<std::string> &cfiFunctionDefs() { return CfiFunctionDefs; }
1040 const std::set<std::string> &cfiFunctionDefs() const { return CfiFunctionDefs; }
1042 std::set<std::string> &cfiFunctionDecls() { return CfiFunctionDecls; }
1043 const std::set<std::string> &cfiFunctionDecls() const { return CfiFunctionDecls; }
1045 /// Add a global value summary for a value.
1046 void addGlobalValueSummary(const GlobalValue &GV,
1047 std::unique_ptr<GlobalValueSummary> Summary) {
1048 addGlobalValueSummary(getOrInsertValueInfo(&GV), std::move(Summary));
1051 /// Add a global value summary for a value of the given name.
1052 void addGlobalValueSummary(StringRef ValueName,
1053 std::unique_ptr<GlobalValueSummary> Summary) {
1054 addGlobalValueSummary(getOrInsertValueInfo(GlobalValue::getGUID(ValueName)),
1055 std::move(Summary));
1058 /// Add a global value summary for the given ValueInfo.
1059 void addGlobalValueSummary(ValueInfo VI,
1060 std::unique_ptr<GlobalValueSummary> Summary) {
1061 addOriginalName(VI.getGUID(), Summary->getOriginalName());
1062 // Here we have a notionally const VI, but the value it points to is owned
1063 // by the non-const *this.
1064 const_cast<GlobalValueSummaryMapTy::value_type *>(VI.getRef())
1065 ->second.SummaryList.push_back(std::move(Summary));
1068 /// Add an original name for the value of the given GUID.
1069 void addOriginalName(GlobalValue::GUID ValueGUID,
1070 GlobalValue::GUID OrigGUID) {
1071 if (OrigGUID == 0 || ValueGUID == OrigGUID)
1073 if (OidGuidMap.count(OrigGUID) && OidGuidMap[OrigGUID] != ValueGUID)
1074 OidGuidMap[OrigGUID] = 0;
1076 OidGuidMap[OrigGUID] = ValueGUID;
1079 /// Find the summary for ValueInfo \p VI in module \p ModuleId, or nullptr if
1081 GlobalValueSummary *findSummaryInModule(ValueInfo VI, StringRef ModuleId) const {
1082 auto SummaryList = VI.getSummaryList();
1084 llvm::find_if(SummaryList,
1085 [&](const std::unique_ptr<GlobalValueSummary> &Summary) {
1086 return Summary->modulePath() == ModuleId;
1088 if (Summary == SummaryList.end())
1090 return Summary->get();
1093 /// Find the summary for global \p GUID in module \p ModuleId, or nullptr if
1095 GlobalValueSummary *findSummaryInModule(GlobalValue::GUID ValueGUID,
1096 StringRef ModuleId) const {
1097 auto CalleeInfo = getValueInfo(ValueGUID);
1099 return nullptr; // This function does not have a summary
1100 return findSummaryInModule(CalleeInfo, ModuleId);
1103 /// Returns the first GlobalValueSummary for \p GV, asserting that there
1104 /// is only one if \p PerModuleIndex.
1105 GlobalValueSummary *getGlobalValueSummary(const GlobalValue &GV,
1106 bool PerModuleIndex = true) const {
1107 assert(GV.hasName() && "Can't get GlobalValueSummary for GV with no name");
1108 return getGlobalValueSummary(GV.getGUID(), PerModuleIndex);
1111 /// Returns the first GlobalValueSummary for \p ValueGUID, asserting that
1113 /// is only one if \p PerModuleIndex.
1114 GlobalValueSummary *getGlobalValueSummary(GlobalValue::GUID ValueGUID,
1115 bool PerModuleIndex = true) const;
1117 /// Table of modules, containing module hash and id.
1118 const StringMap<std::pair<uint64_t, ModuleHash>> &modulePaths() const {
1119 return ModulePathStringTable;
1122 /// Table of modules, containing hash and id.
1123 StringMap<std::pair<uint64_t, ModuleHash>> &modulePaths() {
1124 return ModulePathStringTable;
1127 /// Get the module ID recorded for the given module path.
1128 uint64_t getModuleId(const StringRef ModPath) const {
1129 return ModulePathStringTable.lookup(ModPath).first;
1132 /// Get the module SHA1 hash recorded for the given module path.
1133 const ModuleHash &getModuleHash(const StringRef ModPath) const {
1134 auto It = ModulePathStringTable.find(ModPath);
1135 assert(It != ModulePathStringTable.end() && "Module not registered");
1136 return It->second.second;
1139 /// Convenience method for creating a promoted global name
1140 /// for the given value name of a local, and its original module's ID.
1141 static std::string getGlobalNameForLocal(StringRef Name, ModuleHash ModHash) {
1142 SmallString<256> NewName(Name);
1143 NewName += ".llvm.";
1144 NewName += utostr((uint64_t(ModHash[0]) << 32) |
1145 ModHash[1]); // Take the first 64 bits
1146 return NewName.str();
1149 /// Helper to obtain the unpromoted name for a global value (or the original
1150 /// name if not promoted).
1151 static StringRef getOriginalNameBeforePromote(StringRef Name) {
1152 std::pair<StringRef, StringRef> Pair = Name.split(".llvm.");
1156 typedef ModulePathStringTableTy::value_type ModuleInfo;
1158 /// Add a new module with the given \p Hash, mapped to the given \p
1159 /// ModID, and return a reference to the module.
1160 ModuleInfo *addModule(StringRef ModPath, uint64_t ModId,
1161 ModuleHash Hash = ModuleHash{{0}}) {
1162 return &*ModulePathStringTable.insert({ModPath, {ModId, Hash}}).first;
1165 /// Return module entry for module with the given \p ModPath.
1166 ModuleInfo *getModule(StringRef ModPath) {
1167 auto It = ModulePathStringTable.find(ModPath);
1168 assert(It != ModulePathStringTable.end() && "Module not registered");
1172 /// Check if the given Module has any functions available for exporting
1173 /// in the index. We consider any module present in the ModulePathStringTable
1174 /// to have exported functions.
1175 bool hasExportedFunctions(const Module &M) const {
1176 return ModulePathStringTable.count(M.getModuleIdentifier());
1179 const TypeIdSummaryMapTy &typeIds() const { return TypeIdMap; }
1181 /// Return an existing or new TypeIdSummary entry for \p TypeId.
1182 /// This accessor can mutate the map and therefore should not be used in
1183 /// the ThinLTO backends.
1184 TypeIdSummary &getOrInsertTypeIdSummary(StringRef TypeId) {
1185 auto TidIter = TypeIdMap.equal_range(GlobalValue::getGUID(TypeId));
1186 for (auto It = TidIter.first; It != TidIter.second; ++It)
1187 if (It->second.first == TypeId)
1188 return It->second.second;
1189 auto It = TypeIdMap.insert(
1190 {GlobalValue::getGUID(TypeId), {TypeId, TypeIdSummary()}});
1191 return It->second.second;
1194 /// This returns either a pointer to the type id summary (if present in the
1195 /// summary map) or null (if not present). This may be used when importing.
1196 const TypeIdSummary *getTypeIdSummary(StringRef TypeId) const {
1197 auto TidIter = TypeIdMap.equal_range(GlobalValue::getGUID(TypeId));
1198 for (auto It = TidIter.first; It != TidIter.second; ++It)
1199 if (It->second.first == TypeId)
1200 return &It->second.second;
1204 /// Collect for the given module the list of functions it defines
1205 /// (GUID -> Summary).
1206 void collectDefinedFunctionsForModule(StringRef ModulePath,
1207 GVSummaryMapTy &GVSummaryMap) const;
1209 /// Collect for each module the list of Summaries it defines (GUID ->
1211 template <class Map>
1213 collectDefinedGVSummariesPerModule(Map &ModuleToDefinedGVSummaries) const {
1214 for (auto &GlobalList : *this) {
1215 auto GUID = GlobalList.first;
1216 for (auto &Summary : GlobalList.second.SummaryList) {
1217 ModuleToDefinedGVSummaries[Summary->modulePath()][GUID] = Summary.get();
1222 /// Print to an output stream.
1223 void print(raw_ostream &OS, bool IsForDebug = false) const;
1225 /// Dump to stderr (for debugging).
1228 /// Export summary to dot file for GraphViz.
1229 void exportToDot(raw_ostream& OS) const;
1231 /// Print out strongly connected components for debugging.
1232 void dumpSCCs(raw_ostream &OS);
1234 /// Analyze index and detect unmodified globals
1235 void propagateConstants(const DenseSet<GlobalValue::GUID> &PreservedSymbols);
1238 /// GraphTraits definition to build SCC for the index
1239 template <> struct GraphTraits<ValueInfo> {
1240 typedef ValueInfo NodeRef;
1241 using EdgeRef = FunctionSummary::EdgeTy &;
1243 static NodeRef valueInfoFromEdge(FunctionSummary::EdgeTy &P) {
1246 using ChildIteratorType =
1247 mapped_iterator<std::vector<FunctionSummary::EdgeTy>::iterator,
1248 decltype(&valueInfoFromEdge)>;
1250 using ChildEdgeIteratorType = std::vector<FunctionSummary::EdgeTy>::iterator;
1252 static NodeRef getEntryNode(ValueInfo V) { return V; }
1254 static ChildIteratorType child_begin(NodeRef N) {
1255 if (!N.getSummaryList().size()) // handle external function
1256 return ChildIteratorType(
1257 FunctionSummary::ExternalNode.CallGraphEdgeList.begin(),
1258 &valueInfoFromEdge);
1259 FunctionSummary *F =
1260 cast<FunctionSummary>(N.getSummaryList().front()->getBaseObject());
1261 return ChildIteratorType(F->CallGraphEdgeList.begin(), &valueInfoFromEdge);
1264 static ChildIteratorType child_end(NodeRef N) {
1265 if (!N.getSummaryList().size()) // handle external function
1266 return ChildIteratorType(
1267 FunctionSummary::ExternalNode.CallGraphEdgeList.end(),
1268 &valueInfoFromEdge);
1269 FunctionSummary *F =
1270 cast<FunctionSummary>(N.getSummaryList().front()->getBaseObject());
1271 return ChildIteratorType(F->CallGraphEdgeList.end(), &valueInfoFromEdge);
1274 static ChildEdgeIteratorType child_edge_begin(NodeRef N) {
1275 if (!N.getSummaryList().size()) // handle external function
1276 return FunctionSummary::ExternalNode.CallGraphEdgeList.begin();
1278 FunctionSummary *F =
1279 cast<FunctionSummary>(N.getSummaryList().front()->getBaseObject());
1280 return F->CallGraphEdgeList.begin();
1283 static ChildEdgeIteratorType child_edge_end(NodeRef N) {
1284 if (!N.getSummaryList().size()) // handle external function
1285 return FunctionSummary::ExternalNode.CallGraphEdgeList.end();
1287 FunctionSummary *F =
1288 cast<FunctionSummary>(N.getSummaryList().front()->getBaseObject());
1289 return F->CallGraphEdgeList.end();
1292 static NodeRef edge_dest(EdgeRef E) { return E.first; }
1296 struct GraphTraits<ModuleSummaryIndex *> : public GraphTraits<ValueInfo> {
1297 static NodeRef getEntryNode(ModuleSummaryIndex *I) {
1298 std::unique_ptr<GlobalValueSummary> Root =
1299 make_unique<FunctionSummary>(I->calculateCallGraphRoot());
1300 GlobalValueSummaryInfo G(I->haveGVs());
1301 G.SummaryList.push_back(std::move(Root));
1303 GlobalValueSummaryMapTy::value_type(GlobalValue::GUID(0), std::move(G));
1304 return ValueInfo(I->haveGVs(), &P);
1308 static inline bool canImportGlobalVar(GlobalValueSummary *S) {
1309 assert(isa<GlobalVarSummary>(S->getBaseObject()));
1311 // We don't import GV with references, because it can result
1312 // in promotion of local variables in the source module.
1313 return !GlobalValue::isInterposableLinkage(S->linkage()) &&
1314 !S->notEligibleToImport() && S->refs().empty();
1316 } // end namespace llvm
1318 #endif // LLVM_IR_MODULESUMMARYINDEX_H