1 //===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the LLVM module linker.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Linker.h"
15 #include "llvm/Constants.h"
16 #include "llvm/DerivedTypes.h"
17 #include "llvm/Instructions.h"
18 #include "llvm/Module.h"
19 #include "llvm/ADT/DenseSet.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/SetVector.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include "llvm/Support/Path.h"
25 #include "llvm/Transforms/Utils/Cloning.h"
26 #include "llvm/Transforms/Utils/ValueMapper.h"
30 //===----------------------------------------------------------------------===//
31 // TypeMap implementation.
32 //===----------------------------------------------------------------------===//
35 class TypeMapTy : public ValueMapTypeRemapper {
36 /// MappedTypes - This is a mapping from a source type to a destination type
38 DenseMap<Type*, Type*> MappedTypes;
40 /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic,
41 /// we speculatively add types to MappedTypes, but keep track of them here in
42 /// case we need to roll back.
43 SmallVector<Type*, 16> SpeculativeTypes;
45 /// SrcDefinitionsToResolve - This is a list of non-opaque structs in the
46 /// source module that are mapped to an opaque struct in the destination
48 SmallVector<StructType*, 16> SrcDefinitionsToResolve;
50 /// DstResolvedOpaqueTypes - This is the set of opaque types in the
51 /// destination modules who are getting a body from the source module.
52 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
55 /// addTypeMapping - Indicate that the specified type in the destination
56 /// module is conceptually equivalent to the specified type in the source
58 void addTypeMapping(Type *DstTy, Type *SrcTy);
60 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
61 /// module from a type definition in the source module.
62 void linkDefinedTypeBodies();
64 /// get - Return the mapped type to use for the specified input type from the
66 Type *get(Type *SrcTy);
68 FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));}
71 Type *getImpl(Type *T);
72 /// remapType - Implement the ValueMapTypeRemapper interface.
73 Type *remapType(Type *SrcTy) {
77 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
81 void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
82 Type *&Entry = MappedTypes[SrcTy];
90 // Check to see if these types are recursively isomorphic and establish a
91 // mapping between them if so.
92 if (!areTypesIsomorphic(DstTy, SrcTy)) {
93 // Oops, they aren't isomorphic. Just discard this request by rolling out
94 // any speculative mappings we've established.
95 for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i)
96 MappedTypes.erase(SpeculativeTypes[i]);
98 SpeculativeTypes.clear();
101 /// areTypesIsomorphic - Recursively walk this pair of types, returning true
102 /// if they are isomorphic, false if they are not.
103 bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
104 // Two types with differing kinds are clearly not isomorphic.
105 if (DstTy->getTypeID() != SrcTy->getTypeID()) return false;
107 // If we have an entry in the MappedTypes table, then we have our answer.
108 Type *&Entry = MappedTypes[SrcTy];
110 return Entry == DstTy;
112 // Two identical types are clearly isomorphic. Remember this
113 // non-speculatively.
114 if (DstTy == SrcTy) {
119 // Okay, we have two types with identical kinds that we haven't seen before.
121 // If this is an opaque struct type, special case it.
122 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
123 // Mapping an opaque type to any struct, just keep the dest struct.
124 if (SSTy->isOpaque()) {
126 SpeculativeTypes.push_back(SrcTy);
130 // Mapping a non-opaque source type to an opaque dest. If this is the first
131 // type that we're mapping onto this destination type then we succeed. Keep
132 // the dest, but fill it in later. This doesn't need to be speculative. If
133 // this is the second (different) type that we're trying to map onto the
134 // same opaque type then we fail.
135 if (cast<StructType>(DstTy)->isOpaque()) {
136 // We can only map one source type onto the opaque destination type.
137 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)))
139 SrcDefinitionsToResolve.push_back(SSTy);
145 // If the number of subtypes disagree between the two types, then we fail.
146 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
149 // Fail if any of the extra properties (e.g. array size) of the type disagree.
150 if (isa<IntegerType>(DstTy))
151 return false; // bitwidth disagrees.
152 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
153 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
156 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
157 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
159 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
160 StructType *SSTy = cast<StructType>(SrcTy);
161 if (DSTy->isLiteral() != SSTy->isLiteral() ||
162 DSTy->isPacked() != SSTy->isPacked())
164 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
165 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
167 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
168 if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
172 // Otherwise, we speculate that these two types will line up and recursively
173 // check the subelements.
175 SpeculativeTypes.push_back(SrcTy);
177 for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i)
178 if (!areTypesIsomorphic(DstTy->getContainedType(i),
179 SrcTy->getContainedType(i)))
182 // If everything seems to have lined up, then everything is great.
186 /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
187 /// module from a type definition in the source module.
188 void TypeMapTy::linkDefinedTypeBodies() {
189 SmallVector<Type*, 16> Elements;
190 SmallString<16> TmpName;
192 // Note that processing entries in this loop (calling 'get') can add new
193 // entries to the SrcDefinitionsToResolve vector.
194 while (!SrcDefinitionsToResolve.empty()) {
195 StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val();
196 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
198 // TypeMap is a many-to-one mapping, if there were multiple types that
199 // provide a body for DstSTy then previous iterations of this loop may have
200 // already handled it. Just ignore this case.
201 if (!DstSTy->isOpaque()) continue;
202 assert(!SrcSTy->isOpaque() && "Not resolving a definition?");
204 // Map the body of the source type over to a new body for the dest type.
205 Elements.resize(SrcSTy->getNumElements());
206 for (unsigned i = 0, e = Elements.size(); i != e; ++i)
207 Elements[i] = getImpl(SrcSTy->getElementType(i));
209 DstSTy->setBody(Elements, SrcSTy->isPacked());
211 // If DstSTy has no name or has a longer name than STy, then viciously steal
213 if (!SrcSTy->hasName()) continue;
214 StringRef SrcName = SrcSTy->getName();
216 if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) {
217 TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end());
219 DstSTy->setName(TmpName.str());
224 DstResolvedOpaqueTypes.clear();
228 /// get - Return the mapped type to use for the specified input type from the
230 Type *TypeMapTy::get(Type *Ty) {
231 Type *Result = getImpl(Ty);
233 // If this caused a reference to any struct type, resolve it before returning.
234 if (!SrcDefinitionsToResolve.empty())
235 linkDefinedTypeBodies();
239 /// getImpl - This is the recursive version of get().
240 Type *TypeMapTy::getImpl(Type *Ty) {
241 // If we already have an entry for this type, return it.
242 Type **Entry = &MappedTypes[Ty];
243 if (*Entry) return *Entry;
245 // If this is not a named struct type, then just map all of the elements and
246 // then rebuild the type from inside out.
247 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) {
248 // If there are no element types to map, then the type is itself. This is
249 // true for the anonymous {} struct, things like 'float', integers, etc.
250 if (Ty->getNumContainedTypes() == 0)
253 // Remap all of the elements, keeping track of whether any of them change.
254 bool AnyChange = false;
255 SmallVector<Type*, 4> ElementTypes;
256 ElementTypes.resize(Ty->getNumContainedTypes());
257 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) {
258 ElementTypes[i] = getImpl(Ty->getContainedType(i));
259 AnyChange |= ElementTypes[i] != Ty->getContainedType(i);
262 // If we found our type while recursively processing stuff, just use it.
263 Entry = &MappedTypes[Ty];
264 if (*Entry) return *Entry;
266 // If all of the element types mapped directly over, then the type is usable
271 // Otherwise, rebuild a modified type.
272 switch (Ty->getTypeID()) {
273 default: llvm_unreachable("unknown derived type to remap");
274 case Type::ArrayTyID:
275 return *Entry = ArrayType::get(ElementTypes[0],
276 cast<ArrayType>(Ty)->getNumElements());
277 case Type::VectorTyID:
278 return *Entry = VectorType::get(ElementTypes[0],
279 cast<VectorType>(Ty)->getNumElements());
280 case Type::PointerTyID:
281 return *Entry = PointerType::get(ElementTypes[0],
282 cast<PointerType>(Ty)->getAddressSpace());
283 case Type::FunctionTyID:
284 return *Entry = FunctionType::get(ElementTypes[0],
285 makeArrayRef(ElementTypes).slice(1),
286 cast<FunctionType>(Ty)->isVarArg());
287 case Type::StructTyID:
288 // Note that this is only reached for anonymous structs.
289 return *Entry = StructType::get(Ty->getContext(), ElementTypes,
290 cast<StructType>(Ty)->isPacked());
294 // Otherwise, this is an unmapped named struct. If the struct can be directly
295 // mapped over, just use it as-is. This happens in a case when the linked-in
296 // module has something like:
297 // %T = type {%T*, i32}
298 // @GV = global %T* null
299 // where T does not exist at all in the destination module.
301 // The other case we watch for is when the type is not in the destination
302 // module, but that it has to be rebuilt because it refers to something that
303 // is already mapped. For example, if the destination module has:
305 // and the source module has something like
306 // %A' = type { i32 }
307 // %B = type { %A'* }
308 // @GV = global %B* null
309 // then we want to create a new type: "%B = type { %A*}" and have it take the
310 // pristine "%B" name from the source module.
312 // To determine which case this is, we have to recursively walk the type graph
313 // speculating that we'll be able to reuse it unmodified. Only if this is
314 // safe would we map the entire thing over. Because this is an optimization,
315 // and is not required for the prettiness of the linked module, we just skip
316 // it and always rebuild a type here.
317 StructType *STy = cast<StructType>(Ty);
319 // If the type is opaque, we can just use it directly.
323 // Otherwise we create a new type and resolve its body later. This will be
324 // resolved by the top level of get().
325 SrcDefinitionsToResolve.push_back(STy);
326 StructType *DTy = StructType::create(STy->getContext());
327 DstResolvedOpaqueTypes.insert(DTy);
333 //===----------------------------------------------------------------------===//
334 // ModuleLinker implementation.
335 //===----------------------------------------------------------------------===//
338 /// ModuleLinker - This is an implementation class for the LinkModules
339 /// function, which is the entrypoint for this file.
345 /// ValueMap - Mapping of values from what they used to be in Src, to what
346 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves
347 /// some overhead due to the use of Value handles which the Linker doesn't
348 /// actually need, but this allows us to reuse the ValueMapper code.
349 ValueToValueMapTy ValueMap;
351 struct AppendingVarInfo {
352 GlobalVariable *NewGV; // New aggregate global in dest module.
353 Constant *DstInit; // Old initializer from dest module.
354 Constant *SrcInit; // Old initializer from src module.
357 std::vector<AppendingVarInfo> AppendingVars;
359 unsigned Mode; // Mode to treat source module.
361 // Set of items not to link in from source.
362 SmallPtrSet<const Value*, 16> DoNotLinkFromSource;
364 // Vector of functions to lazily link in.
365 std::vector<Function*> LazilyLinkFunctions;
368 std::string ErrorMsg;
370 ModuleLinker(Module *dstM, Module *srcM, unsigned mode)
371 : DstM(dstM), SrcM(srcM), Mode(mode) { }
376 /// emitError - Helper method for setting a message and returning an error
378 bool emitError(const Twine &Message) {
379 ErrorMsg = Message.str();
383 /// getLinkageResult - This analyzes the two global values and determines
384 /// what the result will look like in the destination module.
385 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
386 GlobalValue::LinkageTypes <,
387 GlobalValue::VisibilityTypes &Vis,
390 /// getLinkedToGlobal - Given a global in the source module, return the
391 /// global in the destination module that is being linked to, if any.
392 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) {
393 // If the source has no name it can't link. If it has local linkage,
394 // there is no name match-up going on.
395 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
398 // Otherwise see if we have a match in the destination module's symtab.
399 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
400 if (DGV == 0) return 0;
402 // If we found a global with the same name in the dest module, but it has
403 // internal linkage, we are really not doing any linkage here.
404 if (DGV->hasLocalLinkage())
407 // Otherwise, we do in fact link to the destination global.
411 void computeTypeMapping();
412 bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
413 DenseMap<MDString*, MDNode*> &ErrorNode,
414 DenseMap<MDString*, MDNode*> &WarningNode,
415 DenseMap<MDString*, MDNode*> &OverrideNode,
417 SmallSetVector<MDNode*, 8> > &RequireNodes,
418 SmallSetVector<MDString*, 16> &SeenIDs);
420 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV);
421 bool linkGlobalProto(GlobalVariable *SrcGV);
422 bool linkFunctionProto(Function *SrcF);
423 bool linkAliasProto(GlobalAlias *SrcA);
424 bool linkModuleFlagsMetadata();
426 void linkAppendingVarInit(const AppendingVarInfo &AVI);
427 void linkGlobalInits();
428 void linkFunctionBody(Function *Dst, Function *Src);
429 void linkAliasBodies();
430 void linkNamedMDNodes();
436 /// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict
437 /// in the symbol table. This is good for all clients except for us. Go
438 /// through the trouble to force this back.
439 static void forceRenaming(GlobalValue *GV, StringRef Name) {
440 // If the global doesn't force its name or if it already has the right name,
441 // there is nothing for us to do.
442 if (GV->hasLocalLinkage() || GV->getName() == Name)
445 Module *M = GV->getParent();
447 // If there is a conflict, rename the conflict.
448 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
449 GV->takeName(ConflictGV);
450 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
451 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
453 GV->setName(Name); // Force the name back
457 /// CopyGVAttributes - copy additional attributes (those not needed to construct
458 /// a GlobalValue) from the SrcGV to the DestGV.
459 static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
460 // Use the maximum alignment, rather than just copying the alignment of SrcGV.
461 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
462 DestGV->copyAttributesFrom(SrcGV);
463 DestGV->setAlignment(Alignment);
465 forceRenaming(DestGV, SrcGV->getName());
468 static bool isLessConstraining(GlobalValue::VisibilityTypes a,
469 GlobalValue::VisibilityTypes b) {
470 if (a == GlobalValue::HiddenVisibility)
472 if (b == GlobalValue::HiddenVisibility)
474 if (a == GlobalValue::ProtectedVisibility)
476 if (b == GlobalValue::ProtectedVisibility)
481 /// getLinkageResult - This analyzes the two global values and determines what
482 /// the result will look like in the destination module. In particular, it
483 /// computes the resultant linkage type and visibility, computes whether the
484 /// global in the source should be copied over to the destination (replacing
485 /// the existing one), and computes whether this linkage is an error or not.
486 bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
487 GlobalValue::LinkageTypes <,
488 GlobalValue::VisibilityTypes &Vis,
490 assert(Dest && "Must have two globals being queried");
491 assert(!Src->hasLocalLinkage() &&
492 "If Src has internal linkage, Dest shouldn't be set!");
494 bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable();
495 bool DestIsDeclaration = Dest->isDeclaration();
497 if (SrcIsDeclaration) {
498 // If Src is external or if both Src & Dest are external.. Just link the
499 // external globals, we aren't adding anything.
500 if (Src->hasDLLImportLinkage()) {
501 // If one of GVs has DLLImport linkage, result should be dllimport'ed.
502 if (DestIsDeclaration) {
504 LT = Src->getLinkage();
506 } else if (Dest->hasExternalWeakLinkage()) {
507 // If the Dest is weak, use the source linkage.
509 LT = Src->getLinkage();
512 LT = Dest->getLinkage();
514 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) {
515 // If Dest is external but Src is not:
517 LT = Src->getLinkage();
518 } else if (Src->isWeakForLinker()) {
519 // At this point we know that Dest has LinkOnce, External*, Weak, Common,
521 if (Dest->hasExternalWeakLinkage() ||
522 Dest->hasAvailableExternallyLinkage() ||
523 (Dest->hasLinkOnceLinkage() &&
524 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
526 LT = Src->getLinkage();
529 LT = Dest->getLinkage();
531 } else if (Dest->isWeakForLinker()) {
532 // At this point we know that Src has External* or DLL* linkage.
533 if (Src->hasExternalWeakLinkage()) {
535 LT = Dest->getLinkage();
538 LT = GlobalValue::ExternalLinkage;
541 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() ||
542 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) &&
543 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() ||
544 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) &&
545 "Unexpected linkage type!");
546 return emitError("Linking globals named '" + Src->getName() +
547 "': symbol multiply defined!");
550 // Compute the visibility. We follow the rules in the System V Application
552 Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ?
553 Dest->getVisibility() : Src->getVisibility();
557 /// computeTypeMapping - Loop over all of the linked values to compute type
558 /// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then
559 /// we have two struct types 'Foo' but one got renamed when the module was
560 /// loaded into the same LLVMContext.
561 void ModuleLinker::computeTypeMapping() {
562 // Incorporate globals.
563 for (Module::global_iterator I = SrcM->global_begin(),
564 E = SrcM->global_end(); I != E; ++I) {
565 GlobalValue *DGV = getLinkedToGlobal(I);
566 if (DGV == 0) continue;
568 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) {
569 TypeMap.addTypeMapping(DGV->getType(), I->getType());
573 // Unify the element type of appending arrays.
574 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
575 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType());
576 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
579 // Incorporate functions.
580 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) {
581 if (GlobalValue *DGV = getLinkedToGlobal(I))
582 TypeMap.addTypeMapping(DGV->getType(), I->getType());
585 // Incorporate types by name, scanning all the types in the source module.
586 // At this point, the destination module may have a type "%foo = { i32 }" for
587 // example. When the source module got loaded into the same LLVMContext, if
588 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
589 // Though it isn't required for correctness, attempt to link these up to clean
591 std::vector<StructType*> SrcStructTypes;
592 SrcM->findUsedStructTypes(SrcStructTypes);
594 SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
595 SrcStructTypes.end());
597 for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
598 StructType *ST = SrcStructTypes[i];
599 if (!ST->hasName()) continue;
601 // Check to see if there is a dot in the name followed by a digit.
602 size_t DotPos = ST->getName().rfind('.');
603 if (DotPos == 0 || DotPos == StringRef::npos ||
604 ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1]))
607 // Check to see if the destination module has a struct with the prefix name.
608 if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
609 // Don't use it if this actually came from the source module. They're in
610 // the same LLVMContext after all.
611 if (!SrcStructTypesSet.count(DST))
612 TypeMap.addTypeMapping(DST, ST);
615 // Don't bother incorporating aliases, they aren't generally typed well.
617 // Now that we have discovered all of the type equivalences, get a body for
618 // any 'opaque' types in the dest module that are now resolved.
619 TypeMap.linkDefinedTypeBodies();
622 /// linkAppendingVarProto - If there were any appending global variables, link
623 /// them together now. Return true on error.
624 bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
625 GlobalVariable *SrcGV) {
627 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
628 return emitError("Linking globals named '" + SrcGV->getName() +
629 "': can only link appending global with another appending global!");
631 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
633 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
634 Type *EltTy = DstTy->getElementType();
636 // Check to see that they two arrays agree on type.
637 if (EltTy != SrcTy->getElementType())
638 return emitError("Appending variables with different element types!");
639 if (DstGV->isConstant() != SrcGV->isConstant())
640 return emitError("Appending variables linked with different const'ness!");
642 if (DstGV->getAlignment() != SrcGV->getAlignment())
644 "Appending variables with different alignment need to be linked!");
646 if (DstGV->getVisibility() != SrcGV->getVisibility())
648 "Appending variables with different visibility need to be linked!");
650 if (DstGV->getSection() != SrcGV->getSection())
652 "Appending variables with different section name need to be linked!");
654 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements();
655 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
657 // Create the new global variable.
659 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
660 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
661 DstGV->isThreadLocal(),
662 DstGV->getType()->getAddressSpace());
664 // Propagate alignment, visibility and section info.
665 CopyGVAttributes(NG, DstGV);
667 AppendingVarInfo AVI;
669 AVI.DstInit = DstGV->getInitializer();
670 AVI.SrcInit = SrcGV->getInitializer();
671 AppendingVars.push_back(AVI);
673 // Replace any uses of the two global variables with uses of the new
675 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
677 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
678 DstGV->eraseFromParent();
680 // Track the source variable so we don't try to link it.
681 DoNotLinkFromSource.insert(SrcGV);
686 /// linkGlobalProto - Loop through the global variables in the src module and
687 /// merge them into the dest module.
688 bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
689 GlobalValue *DGV = getLinkedToGlobal(SGV);
690 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
693 // Concatenation of appending linkage variables is magic and handled later.
694 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
695 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
697 // Determine whether linkage of these two globals follows the source
698 // module's definition or the destination module's definition.
699 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
700 GlobalValue::VisibilityTypes NV;
701 bool LinkFromSrc = false;
702 if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
706 // If we're not linking from the source, then keep the definition that we
709 // Special case for const propagation.
710 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
711 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
712 DGVar->setConstant(true);
714 // Set calculated linkage and visibility.
715 DGV->setLinkage(NewLinkage);
716 DGV->setVisibility(*NewVisibility);
718 // Make sure to remember this mapping.
719 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
721 // Track the source global so that we don't attempt to copy it over when
722 // processing global initializers.
723 DoNotLinkFromSource.insert(SGV);
729 // No linking to be performed or linking from the source: simply create an
730 // identical version of the symbol over in the dest module... the
731 // initializer will be filled in later by LinkGlobalInits.
732 GlobalVariable *NewDGV =
733 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
734 SGV->isConstant(), SGV->getLinkage(), /*init*/0,
735 SGV->getName(), /*insertbefore*/0,
736 SGV->isThreadLocal(),
737 SGV->getType()->getAddressSpace());
738 // Propagate alignment, visibility and section info.
739 CopyGVAttributes(NewDGV, SGV);
741 NewDGV->setVisibility(*NewVisibility);
744 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
745 DGV->eraseFromParent();
748 // Make sure to remember this mapping.
749 ValueMap[SGV] = NewDGV;
753 /// linkFunctionProto - Link the function in the source module into the
754 /// destination module if needed, setting up mapping information.
755 bool ModuleLinker::linkFunctionProto(Function *SF) {
756 GlobalValue *DGV = getLinkedToGlobal(SF);
757 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
760 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
761 bool LinkFromSrc = false;
762 GlobalValue::VisibilityTypes NV;
763 if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
768 // Set calculated linkage
769 DGV->setLinkage(NewLinkage);
770 DGV->setVisibility(*NewVisibility);
772 // Make sure to remember this mapping.
773 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
775 // Track the function from the source module so we don't attempt to remap
777 DoNotLinkFromSource.insert(SF);
783 // If there is no linkage to be performed or we are linking from the source,
785 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
786 SF->getLinkage(), SF->getName(), DstM);
787 CopyGVAttributes(NewDF, SF);
789 NewDF->setVisibility(*NewVisibility);
792 // Any uses of DF need to change to NewDF, with cast.
793 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
794 DGV->eraseFromParent();
796 // Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link.
797 if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
798 SF->hasAvailableExternallyLinkage()) {
799 DoNotLinkFromSource.insert(SF);
800 LazilyLinkFunctions.push_back(SF);
804 ValueMap[SF] = NewDF;
808 /// LinkAliasProto - Set up prototypes for any aliases that come over from the
810 bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
811 GlobalValue *DGV = getLinkedToGlobal(SGA);
812 llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
815 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
816 GlobalValue::VisibilityTypes NV;
817 bool LinkFromSrc = false;
818 if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
823 // Set calculated linkage.
824 DGV->setLinkage(NewLinkage);
825 DGV->setVisibility(*NewVisibility);
827 // Make sure to remember this mapping.
828 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
830 // Track the alias from the source module so we don't attempt to remap it.
831 DoNotLinkFromSource.insert(SGA);
837 // If there is no linkage to be performed or we're linking from the source,
839 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
840 SGA->getLinkage(), SGA->getName(),
842 CopyGVAttributes(NewDA, SGA);
844 NewDA->setVisibility(*NewVisibility);
847 // Any uses of DGV need to change to NewDA, with cast.
848 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType()));
849 DGV->eraseFromParent();
852 ValueMap[SGA] = NewDA;
856 static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) {
857 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
859 for (unsigned i = 0; i != NumElements; ++i)
860 Dest.push_back(C->getAggregateElement(i));
863 void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) {
864 // Merge the initializer.
865 SmallVector<Constant*, 16> Elements;
866 getArrayElements(AVI.DstInit, Elements);
868 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap);
869 getArrayElements(SrcInit, Elements);
871 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType());
872 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements));
876 // linkGlobalInits - Update the initializers in the Dest module now that all
877 // globals that may be referenced are in Dest.
878 void ModuleLinker::linkGlobalInits() {
879 // Loop over all of the globals in the src module, mapping them over as we go
880 for (Module::const_global_iterator I = SrcM->global_begin(),
881 E = SrcM->global_end(); I != E; ++I) {
883 // Only process initialized GV's or ones not already in dest.
884 if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;
886 // Grab destination global variable.
887 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
888 // Figure out what the initializer looks like in the dest module.
889 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
894 // linkFunctionBody - Copy the source function over into the dest function and
895 // fix up references to values. At this point we know that Dest is an external
896 // function, and that Src is not.
897 void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
898 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration());
900 // Go through and convert function arguments over, remembering the mapping.
901 Function::arg_iterator DI = Dst->arg_begin();
902 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
904 DI->setName(I->getName()); // Copy the name over.
906 // Add a mapping to our mapping.
910 if (Mode == Linker::DestroySource) {
911 // Splice the body of the source function into the dest function.
912 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
914 // At this point, all of the instructions and values of the function are now
915 // copied over. The only problem is that they are still referencing values in
916 // the Source function as operands. Loop through all of the operands of the
917 // functions and patch them up to point to the local versions.
918 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB)
919 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
920 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap);
923 // Clone the body of the function into the dest function.
924 SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
925 CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap);
928 // There is no need to map the arguments anymore.
929 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
936 void ModuleLinker::linkAliasBodies() {
937 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end();
939 if (DoNotLinkFromSource.count(I))
941 if (Constant *Aliasee = I->getAliasee()) {
942 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]);
943 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap));
948 /// linkNamedMDNodes - Insert all of the named mdnodes in Src into the Dest
950 void ModuleLinker::linkNamedMDNodes() {
951 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
952 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
953 E = SrcM->named_metadata_end(); I != E; ++I) {
954 // Don't link module flags here. Do them separately.
955 if (&*I == SrcModFlags) continue;
956 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
957 // Add Src elements into Dest node.
958 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
959 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap,
964 /// categorizeModuleFlagNodes -
966 categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
967 DenseMap<MDString*, MDNode*> &ErrorNode,
968 DenseMap<MDString*, MDNode*> &WarningNode,
969 DenseMap<MDString*, MDNode*> &OverrideNode,
971 SmallSetVector<MDNode*, 8> > &RequireNodes,
972 SmallSetVector<MDString*, 16> &SeenIDs) {
975 for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) {
976 MDNode *Op = ModFlags->getOperand(I);
977 assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!");
978 assert(isa<ConstantInt>(Op->getOperand(0)) &&
979 "Module flag's first operand must be an integer!");
980 assert(isa<MDString>(Op->getOperand(1)) &&
981 "Module flag's second operand must be an MDString!");
983 ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0));
984 MDString *ID = cast<MDString>(Op->getOperand(1));
985 Value *Val = Op->getOperand(2);
986 switch (Behavior->getZExtValue()) {
988 assert(false && "Invalid behavior in module flag metadata!");
990 case Module::Error: {
991 MDNode *&ErrNode = ErrorNode[ID];
992 if (!ErrNode) ErrNode = Op;
993 if (ErrNode->getOperand(2) != Val)
994 HasErr = emitError("linking module flags '" + ID->getString() +
995 "': IDs have conflicting values");
998 case Module::Warning: {
999 MDNode *&WarnNode = WarningNode[ID];
1000 if (!WarnNode) WarnNode = Op;
1001 if (WarnNode->getOperand(2) != Val)
1002 errs() << "WARNING: linking module flags '" << ID->getString()
1003 << "': IDs have conflicting values";
1006 case Module::Require: RequireNodes[ID].insert(Op); break;
1007 case Module::Override: {
1008 MDNode *&OvrNode = OverrideNode[ID];
1009 if (!OvrNode) OvrNode = Op;
1010 if (OvrNode->getOperand(2) != Val)
1011 HasErr = emitError("linking module flags '" + ID->getString() +
1012 "': IDs have conflicting override values");
1023 /// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest
1025 bool ModuleLinker::linkModuleFlagsMetadata() {
1026 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1027 if (!SrcModFlags) return false;
1029 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
1031 // If the destination module doesn't have module flags yet, then just copy
1032 // over the source module's flags.
1033 if (DstModFlags->getNumOperands() == 0) {
1034 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1035 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1040 bool HasErr = false;
1042 // Otherwise, we have to merge them based on their behaviors. First,
1043 // categorize all of the nodes in the modules' module flags. If an error or
1044 // warning occurs, then emit the appropriate message(s).
1045 DenseMap<MDString*, MDNode*> ErrorNode;
1046 DenseMap<MDString*, MDNode*> WarningNode;
1047 DenseMap<MDString*, MDNode*> OverrideNode;
1048 DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes;
1049 SmallSetVector<MDString*, 16> SeenIDs;
1051 HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode,
1052 OverrideNode, RequireNodes, SeenIDs);
1053 HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode,
1054 OverrideNode, RequireNodes, SeenIDs);
1056 // Check that there isn't both an error and warning node for a flag.
1057 for (SmallSetVector<MDString*, 16>::iterator
1058 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
1060 if (ErrorNode[ID] && WarningNode[ID])
1061 HasErr = emitError("linking module flags '" + ID->getString() +
1062 "': IDs have conflicting behaviors");
1065 // Early exit if we had an error.
1066 if (HasErr) return true;
1068 // Get the destination's module flags ready for new operands.
1069 DstModFlags->dropAllReferences();
1071 // Add all of the module flags to the destination module.
1072 DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes;
1073 for (SmallSetVector<MDString*, 16>::iterator
1074 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
1076 if (OverrideNode[ID]) {
1077 DstModFlags->addOperand(OverrideNode[ID]);
1078 AddedNodes[ID].push_back(OverrideNode[ID]);
1079 } else if (ErrorNode[ID]) {
1080 DstModFlags->addOperand(ErrorNode[ID]);
1081 AddedNodes[ID].push_back(ErrorNode[ID]);
1082 } else if (WarningNode[ID]) {
1083 DstModFlags->addOperand(WarningNode[ID]);
1084 AddedNodes[ID].push_back(WarningNode[ID]);
1087 for (SmallSetVector<MDNode*, 8>::iterator
1088 II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end();
1090 DstModFlags->addOperand(*II);
1093 // Now check that all of the requirements have been satisfied.
1094 for (SmallSetVector<MDString*, 16>::iterator
1095 I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
1097 SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID];
1099 for (SmallSetVector<MDNode*, 8>::iterator
1100 II = Set.begin(), IE = Set.end(); II != IE; ++II) {
1102 assert(isa<MDNode>(Node->getOperand(2)) &&
1103 "Module flag's third operand must be an MDNode!");
1104 MDNode *Val = cast<MDNode>(Node->getOperand(2));
1106 MDString *ReqID = cast<MDString>(Val->getOperand(0));
1107 Value *ReqVal = Val->getOperand(1);
1109 bool HasValue = false;
1110 for (SmallVectorImpl<MDNode*>::iterator
1111 RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end();
1113 MDNode *ReqNode = *RI;
1114 if (ReqNode->getOperand(2) == ReqVal) {
1121 HasErr = emitError("linking module flags '" + ReqID->getString() +
1122 "': does not have the required value");
1129 bool ModuleLinker::run() {
1130 assert(DstM && "Null destination module");
1131 assert(SrcM && "Null source module");
1133 // Inherit the target data from the source module if the destination module
1134 // doesn't have one already.
1135 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty())
1136 DstM->setDataLayout(SrcM->getDataLayout());
1138 // Copy the target triple from the source to dest if the dest's is empty.
1139 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
1140 DstM->setTargetTriple(SrcM->getTargetTriple());
1142 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() &&
1143 SrcM->getDataLayout() != DstM->getDataLayout())
1144 errs() << "WARNING: Linking two modules of different data layouts!\n";
1145 if (!SrcM->getTargetTriple().empty() &&
1146 DstM->getTargetTriple() != SrcM->getTargetTriple()) {
1147 errs() << "WARNING: Linking two modules of different target triples: ";
1148 if (!SrcM->getModuleIdentifier().empty())
1149 errs() << SrcM->getModuleIdentifier() << ": ";
1150 errs() << "'" << SrcM->getTargetTriple() << "' and '"
1151 << DstM->getTargetTriple() << "'\n";
1154 // Append the module inline asm string.
1155 if (!SrcM->getModuleInlineAsm().empty()) {
1156 if (DstM->getModuleInlineAsm().empty())
1157 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
1159 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
1160 SrcM->getModuleInlineAsm());
1163 // Update the destination module's dependent libraries list with the libraries
1164 // from the source module. There's no opportunity for duplicates here as the
1165 // Module ensures that duplicate insertions are discarded.
1166 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end();
1168 DstM->addLibrary(*SI);
1170 // If the source library's module id is in the dependent library list of the
1171 // destination library, remove it since that module is now linked in.
1172 StringRef ModuleId = SrcM->getModuleIdentifier();
1173 if (!ModuleId.empty())
1174 DstM->removeLibrary(sys::path::stem(ModuleId));
1176 // Loop over all of the linked values to compute type mappings.
1177 computeTypeMapping();
1179 // Insert all of the globals in src into the DstM module... without linking
1180 // initializers (which could refer to functions not yet mapped over).
1181 for (Module::global_iterator I = SrcM->global_begin(),
1182 E = SrcM->global_end(); I != E; ++I)
1183 if (linkGlobalProto(I))
1186 // Link the functions together between the two modules, without doing function
1187 // bodies... this just adds external function prototypes to the DstM
1188 // function... We do this so that when we begin processing function bodies,
1189 // all of the global values that may be referenced are available in our
1191 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I)
1192 if (linkFunctionProto(I))
1195 // If there were any aliases, link them now.
1196 for (Module::alias_iterator I = SrcM->alias_begin(),
1197 E = SrcM->alias_end(); I != E; ++I)
1198 if (linkAliasProto(I))
1201 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
1202 linkAppendingVarInit(AppendingVars[i]);
1204 // Update the initializers in the DstM module now that all globals that may
1205 // be referenced are in DstM.
1208 // Link in the function bodies that are defined in the source module into
1210 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
1211 // Skip if not linking from source.
1212 if (DoNotLinkFromSource.count(SF)) continue;
1214 // Skip if no body (function is external) or materialize.
1215 if (SF->isDeclaration()) {
1216 if (!SF->isMaterializable())
1218 if (SF->Materialize(&ErrorMsg))
1222 linkFunctionBody(cast<Function>(ValueMap[SF]), SF);
1225 // Resolve all uses of aliases with aliasees.
1228 // Remap all of the named MDNodes in Src into the DstM module. We do this
1229 // after linking GlobalValues so that MDNodes that reference GlobalValues
1230 // are properly remapped.
1233 // Merge the module flags into the DstM module.
1234 if (linkModuleFlagsMetadata())
1237 // Process vector of lazily linked in functions.
1238 bool LinkedInAnyFunctions;
1240 LinkedInAnyFunctions = false;
1242 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1243 E = LazilyLinkFunctions.end(); I != E; ++I) {
1248 Function *DF = cast<Function>(ValueMap[SF]);
1250 if (!DF->use_empty()) {
1252 // Materialize if necessary.
1253 if (SF->isDeclaration()) {
1254 if (!SF->isMaterializable())
1256 if (SF->Materialize(&ErrorMsg))
1260 // Link in function body.
1261 linkFunctionBody(DF, SF);
1263 // "Remove" from vector by setting the element to 0.
1266 // Set flag to indicate we may have more functions to lazily link in
1267 // since we linked in a function.
1268 LinkedInAnyFunctions = true;
1271 } while (LinkedInAnyFunctions);
1273 // Remove any prototypes of functions that were not actually linked in.
1274 for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
1275 E = LazilyLinkFunctions.end(); I != E; ++I) {
1280 Function *DF = cast<Function>(ValueMap[SF]);
1281 if (DF->use_empty())
1282 DF->eraseFromParent();
1285 // Now that all of the types from the source are used, resolve any structs
1286 // copied over to the dest that didn't exist there.
1287 TypeMap.linkDefinedTypeBodies();
1292 //===----------------------------------------------------------------------===//
1293 // LinkModules entrypoint.
1294 //===----------------------------------------------------------------------===//
1296 // LinkModules - This function links two modules together, with the resulting
1297 // left module modified to be the composite of the two input modules. If an
1298 // error occurs, true is returned and ErrorMsg (if not null) is set to indicate
1299 // the problem. Upon failure, the Dest module could be in a modified state, and
1300 // shouldn't be relied on to be consistent.
1301 bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode,
1302 std::string *ErrorMsg) {
1303 ModuleLinker TheLinker(Dest, Src, Mode);
1304 if (TheLinker.run()) {
1305 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg;