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Diffstat (limited to 'lib/Linker/LinkModules.cpp')
| -rw-r--r-- | lib/Linker/LinkModules.cpp | 909 |
1 files changed, 909 insertions, 0 deletions
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp new file mode 100644 index 0000000000..d20044fa3c --- /dev/null +++ b/lib/Linker/LinkModules.cpp @@ -0,0 +1,909 @@ +//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by the LLVM research group and is distributed under +// the University of Illinois Open Source License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the LLVM module linker. +// +// Specifically, this: +// * Merges global variables between the two modules +// * Uninit + Uninit = Init, Init + Uninit = Init, Init + Init = Error if != +// * Merges functions between two modules +// +//===----------------------------------------------------------------------===// + +#include "llvm/Linker.h" +#include "llvm/Constants.h" +#include "llvm/DerivedTypes.h" +#include "llvm/Module.h" +#include "llvm/SymbolTable.h" +#include "llvm/Instructions.h" +#include "llvm/Assembly/Writer.h" +#include "llvm/System/Path.h" +#include <iostream> +#include <sstream> +using namespace llvm; + +// Error - Simple wrapper function to conditionally assign to E and return true. +// This just makes error return conditions a little bit simpler... +static inline bool Error(std::string *E, const std::string &Message) { + if (E) *E = Message; + return true; +} + +// ToStr - Simple wrapper function to convert a type to a string. +static std::string ToStr(const Type *Ty, const Module *M) { + std::ostringstream OS; + WriteTypeSymbolic(OS, Ty, M); + return OS.str(); +} + +// +// Function: ResolveTypes() +// +// Description: +// Attempt to link the two specified types together. +// +// Inputs: +// DestTy - The type to which we wish to resolve. +// SrcTy - The original type which we want to resolve. +// Name - The name of the type. +// +// Outputs: +// DestST - The symbol table in which the new type should be placed. +// +// Return value: +// true - There is an error and the types cannot yet be linked. +// false - No errors. +// +static bool ResolveTypes(const Type *DestTy, const Type *SrcTy, + SymbolTable *DestST, const std::string &Name) { + if (DestTy == SrcTy) return false; // If already equal, noop + + // Does the type already exist in the module? + if (DestTy && !isa<OpaqueType>(DestTy)) { // Yup, the type already exists... + if (const OpaqueType *OT = dyn_cast<OpaqueType>(SrcTy)) { + const_cast<OpaqueType*>(OT)->refineAbstractTypeTo(DestTy); + } else { + return true; // Cannot link types... neither is opaque and not-equal + } + } else { // Type not in dest module. Add it now. + if (DestTy) // Type _is_ in module, just opaque... + const_cast<OpaqueType*>(cast<OpaqueType>(DestTy)) + ->refineAbstractTypeTo(SrcTy); + else if (!Name.empty()) + DestST->insert(Name, const_cast<Type*>(SrcTy)); + } + return false; +} + +static const FunctionType *getFT(const PATypeHolder &TH) { + return cast<FunctionType>(TH.get()); +} +static const StructType *getST(const PATypeHolder &TH) { + return cast<StructType>(TH.get()); +} + +// RecursiveResolveTypes - This is just like ResolveTypes, except that it +// recurses down into derived types, merging the used types if the parent types +// are compatible. +static bool RecursiveResolveTypesI(const PATypeHolder &DestTy, + const PATypeHolder &SrcTy, + SymbolTable *DestST, const std::string &Name, + std::vector<std::pair<PATypeHolder, PATypeHolder> > &Pointers) { + const Type *SrcTyT = SrcTy.get(); + const Type *DestTyT = DestTy.get(); + if (DestTyT == SrcTyT) return false; // If already equal, noop + + // If we found our opaque type, resolve it now! + if (isa<OpaqueType>(DestTyT) || isa<OpaqueType>(SrcTyT)) + return ResolveTypes(DestTyT, SrcTyT, DestST, Name); + + // Two types cannot be resolved together if they are of different primitive + // type. For example, we cannot resolve an int to a float. + if (DestTyT->getTypeID() != SrcTyT->getTypeID()) return true; + + // Otherwise, resolve the used type used by this derived type... + switch (DestTyT->getTypeID()) { + case Type::FunctionTyID: { + if (cast<FunctionType>(DestTyT)->isVarArg() != + cast<FunctionType>(SrcTyT)->isVarArg() || + cast<FunctionType>(DestTyT)->getNumContainedTypes() != + cast<FunctionType>(SrcTyT)->getNumContainedTypes()) + return true; + for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i) + if (RecursiveResolveTypesI(getFT(DestTy)->getContainedType(i), + getFT(SrcTy)->getContainedType(i), DestST, "", + Pointers)) + return true; + return false; + } + case Type::StructTyID: { + if (getST(DestTy)->getNumContainedTypes() != + getST(SrcTy)->getNumContainedTypes()) return 1; + for (unsigned i = 0, e = getST(DestTy)->getNumContainedTypes(); i != e; ++i) + if (RecursiveResolveTypesI(getST(DestTy)->getContainedType(i), + getST(SrcTy)->getContainedType(i), DestST, "", + Pointers)) + return true; + return false; + } + case Type::ArrayTyID: { + const ArrayType *DAT = cast<ArrayType>(DestTy.get()); + const ArrayType *SAT = cast<ArrayType>(SrcTy.get()); + if (DAT->getNumElements() != SAT->getNumElements()) return true; + return RecursiveResolveTypesI(DAT->getElementType(), SAT->getElementType(), + DestST, "", Pointers); + } + case Type::PointerTyID: { + // If this is a pointer type, check to see if we have already seen it. If + // so, we are in a recursive branch. Cut off the search now. We cannot use + // an associative container for this search, because the type pointers (keys + // in the container) change whenever types get resolved... + for (unsigned i = 0, e = Pointers.size(); i != e; ++i) + if (Pointers[i].first == DestTy) + return Pointers[i].second != SrcTy; + + // Otherwise, add the current pointers to the vector to stop recursion on + // this pair. + Pointers.push_back(std::make_pair(DestTyT, SrcTyT)); + bool Result = + RecursiveResolveTypesI(cast<PointerType>(DestTy.get())->getElementType(), + cast<PointerType>(SrcTy.get())->getElementType(), + DestST, "", Pointers); + Pointers.pop_back(); + return Result; + } + default: assert(0 && "Unexpected type!"); return true; + } +} + +static bool RecursiveResolveTypes(const PATypeHolder &DestTy, + const PATypeHolder &SrcTy, + SymbolTable *DestST, const std::string &Name){ + std::vector<std::pair<PATypeHolder, PATypeHolder> > PointerTypes; + return RecursiveResolveTypesI(DestTy, SrcTy, DestST, Name, PointerTypes); +} + + +// LinkTypes - Go through the symbol table of the Src module and see if any +// types are named in the src module that are not named in the Dst module. +// Make sure there are no type name conflicts. +static bool LinkTypes(Module *Dest, const Module *Src, std::string *Err) { + SymbolTable *DestST = &Dest->getSymbolTable(); + const SymbolTable *SrcST = &Src->getSymbolTable(); + + // Look for a type plane for Type's... + SymbolTable::type_const_iterator TI = SrcST->type_begin(); + SymbolTable::type_const_iterator TE = SrcST->type_end(); + if (TI == TE) return false; // No named types, do nothing. + + // Some types cannot be resolved immediately because they depend on other + // types being resolved to each other first. This contains a list of types we + // are waiting to recheck. + std::vector<std::string> DelayedTypesToResolve; + + for ( ; TI != TE; ++TI ) { + const std::string &Name = TI->first; + const Type *RHS = TI->second; + + // Check to see if this type name is already in the dest module... + Type *Entry = DestST->lookupType(Name); + + if (ResolveTypes(Entry, RHS, DestST, Name)) { + // They look different, save the types 'till later to resolve. + DelayedTypesToResolve.push_back(Name); + } + } + + // Iteratively resolve types while we can... + while (!DelayedTypesToResolve.empty()) { + // Loop over all of the types, attempting to resolve them if possible... + unsigned OldSize = DelayedTypesToResolve.size(); + + // Try direct resolution by name... + for (unsigned i = 0; i != DelayedTypesToResolve.size(); ++i) { + const std::string &Name = DelayedTypesToResolve[i]; + Type *T1 = SrcST->lookupType(Name); + Type *T2 = DestST->lookupType(Name); + if (!ResolveTypes(T2, T1, DestST, Name)) { + // We are making progress! + DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); + --i; + } + } + + // Did we not eliminate any types? + if (DelayedTypesToResolve.size() == OldSize) { + // Attempt to resolve subelements of types. This allows us to merge these + // two types: { int* } and { opaque* } + for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) { + const std::string &Name = DelayedTypesToResolve[i]; + PATypeHolder T1(SrcST->lookupType(Name)); + PATypeHolder T2(DestST->lookupType(Name)); + + if (!RecursiveResolveTypes(T2, T1, DestST, Name)) { + // We are making progress! + DelayedTypesToResolve.erase(DelayedTypesToResolve.begin()+i); + + // Go back to the main loop, perhaps we can resolve directly by name + // now... + break; + } + } + + // If we STILL cannot resolve the types, then there is something wrong. + if (DelayedTypesToResolve.size() == OldSize) { + // Remove the symbol name from the destination. + DelayedTypesToResolve.pop_back(); + } + } + } + + + return false; +} + +static void PrintMap(const std::map<const Value*, Value*> &M) { + for (std::map<const Value*, Value*>::const_iterator I = M.begin(), E =M.end(); + I != E; ++I) { + std::cerr << " Fr: " << (void*)I->first << " "; + I->first->dump(); + std::cerr << " To: " << (void*)I->second << " "; + I->second->dump(); + std::cerr << "\n"; + } +} + + +// RemapOperand - Use ValueMap to convert references from one module to another. +// This is somewhat sophisticated in that it can automatically handle constant +// references correctly as well... +static Value *RemapOperand(const Value *In, + std::map<const Value*, Value*> &ValueMap) { + std::map<const Value*,Value*>::const_iterator I = ValueMap.find(In); + if (I != ValueMap.end()) return I->second; + + // Check to see if it's a constant that we are interesting in transforming. + if (const Constant *CPV = dyn_cast<Constant>(In)) { + if ((!isa<DerivedType>(CPV->getType()) && !isa<ConstantExpr>(CPV)) || + isa<ConstantAggregateZero>(CPV)) + return const_cast<Constant*>(CPV); // Simple constants stay identical. + + Constant *Result = 0; + + if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) { + std::vector<Constant*> Operands(CPA->getNumOperands()); + for (unsigned i = 0, e = CPA->getNumOperands(); i != e; ++i) + Operands[i] =cast<Constant>(RemapOperand(CPA->getOperand(i), ValueMap)); + Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands); + } else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) { + std::vector<Constant*> Operands(CPS->getNumOperands()); + for (unsigned i = 0, e = CPS->getNumOperands(); i != e; ++i) + Operands[i] =cast<Constant>(RemapOperand(CPS->getOperand(i), ValueMap)); + Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands); + } else if (isa<ConstantPointerNull>(CPV) || isa<UndefValue>(CPV)) { + Result = const_cast<Constant*>(CPV); + } else if (isa<GlobalValue>(CPV)) { + Result = cast<Constant>(RemapOperand(CPV, ValueMap)); + } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) { + if (CE->getOpcode() == Instruction::GetElementPtr) { + Value *Ptr = RemapOperand(CE->getOperand(0), ValueMap); + std::vector<Constant*> Indices; + Indices.reserve(CE->getNumOperands()-1); + for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) + Indices.push_back(cast<Constant>(RemapOperand(CE->getOperand(i), + ValueMap))); + + Result = ConstantExpr::getGetElementPtr(cast<Constant>(Ptr), Indices); + } else if (CE->getNumOperands() == 1) { + // Cast instruction + assert(CE->getOpcode() == Instruction::Cast); + Value *V = RemapOperand(CE->getOperand(0), ValueMap); + Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType()); + } else if (CE->getNumOperands() == 3) { + // Select instruction + assert(CE->getOpcode() == Instruction::Select); + Value *V1 = RemapOperand(CE->getOperand(0), ValueMap); + Value *V2 = RemapOperand(CE->getOperand(1), ValueMap); + Value *V3 = RemapOperand(CE->getOperand(2), ValueMap); + Result = ConstantExpr::getSelect(cast<Constant>(V1), cast<Constant>(V2), + cast<Constant>(V3)); + } else if (CE->getNumOperands() == 2) { + // Binary operator... + Value *V1 = RemapOperand(CE->getOperand(0), ValueMap); + Value *V2 = RemapOperand(CE->getOperand(1), ValueMap); + + Result = ConstantExpr::get(CE->getOpcode(), cast<Constant>(V1), + cast<Constant>(V2)); + } else { + assert(0 && "Unknown constant expr type!"); + } + + } else { + assert(0 && "Unknown type of derived type constant value!"); + } + + // Cache the mapping in our local map structure... + ValueMap.insert(std::make_pair(In, Result)); + return Result; + } + + std::cerr << "LinkModules ValueMap: \n"; + PrintMap(ValueMap); + + std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n"; + assert(0 && "Couldn't remap value!"); + return 0; +} + +/// ForceRenaming - The LLVM SymbolTable class autorenames globals that conflict +/// in the symbol table. This is good for all clients except for us. Go +/// through the trouble to force this back. +static void ForceRenaming(GlobalValue *GV, const std::string &Name) { + assert(GV->getName() != Name && "Can't force rename to self"); + SymbolTable &ST = GV->getParent()->getSymbolTable(); + + // If there is a conflict, rename the conflict. + Value *ConflictVal = ST.lookup(GV->getType(), Name); + assert(ConflictVal&&"Why do we have to force rename if there is no conflic?"); + GlobalValue *ConflictGV = cast<GlobalValue>(ConflictVal); + assert(ConflictGV->hasInternalLinkage() && + "Not conflicting with a static global, should link instead!"); + + ConflictGV->setName(""); // Eliminate the conflict + GV->setName(Name); // Force the name back + ConflictGV->setName(Name); // This will cause ConflictGV to get renamed + assert(GV->getName() == Name && ConflictGV->getName() != Name && + "ForceRenaming didn't work"); +} + +/// GetLinkageResult - This analyzes the two global values and determines what +/// the result will look like in the destination module. In particular, it +/// computes the resultant linkage type, computes whether the global in the +/// source should be copied over to the destination (replacing the existing +/// one), and computes whether this linkage is an error or not. +static bool GetLinkageResult(GlobalValue *Dest, GlobalValue *Src, + GlobalValue::LinkageTypes <, bool &LinkFromSrc, + std::string *Err) { + assert((!Dest || !Src->hasInternalLinkage()) && + "If Src has internal linkage, Dest shouldn't be set!"); + if (!Dest) { + // Linking something to nothing. + LinkFromSrc = true; + LT = Src->getLinkage(); + } else if (Src->isExternal()) { + // If Src is external or if both Src & Drc are external.. Just link the + // external globals, we aren't adding anything. + LinkFromSrc = false; + LT = Dest->getLinkage(); + } else if (Dest->isExternal()) { + // If Dest is external but Src is not: + LinkFromSrc = true; + LT = Src->getLinkage(); + } else if (Src->hasAppendingLinkage() || Dest->hasAppendingLinkage()) { + if (Src->getLinkage() != Dest->getLinkage()) + return Error(Err, "Linking globals named '" + Src->getName() + + "': can only link appending global with another appending global!"); + LinkFromSrc = true; // Special cased. + LT = Src->getLinkage(); + } else if (Src->hasWeakLinkage() || Src->hasLinkOnceLinkage()) { + // At this point we know that Dest has LinkOnce, External or Weak linkage. + if (Dest->hasLinkOnceLinkage() && Src->hasWeakLinkage()) { + LinkFromSrc = true; + LT = Src->getLinkage(); + } else { + LinkFromSrc = false; + LT = Dest->getLinkage(); + } + } else if (Dest->hasWeakLinkage() || Dest->hasLinkOnceLinkage()) { + // At this point we know that Src has External linkage. + LinkFromSrc = true; + LT = GlobalValue::ExternalLinkage; + } else { + assert(Dest->hasExternalLinkage() && Src->hasExternalLinkage() && + "Unexpected linkage type!"); + return Error(Err, "Linking globals named '" + Src->getName() + + "': symbol multiply defined!"); + } + return false; +} + +// LinkGlobals - Loop through the global variables in the src module and merge +// them into the dest module. +static bool LinkGlobals(Module *Dest, Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::multimap<std::string, GlobalVariable *> &AppendingVars, + std::map<std::string, GlobalValue*> &GlobalsByName, + std::string *Err) { + // We will need a module level symbol table if the src module has a module + // level symbol table... + SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); + + // Loop over all of the globals in the src module, mapping them over as we go + for (Module::global_iterator I = Src->global_begin(), E = Src->global_end(); I != E; ++I) { + GlobalVariable *SGV = I; + GlobalVariable *DGV = 0; + // Check to see if may have to link the global. + if (SGV->hasName() && !SGV->hasInternalLinkage()) + if (!(DGV = Dest->getGlobalVariable(SGV->getName(), + SGV->getType()->getElementType()))) { + std::map<std::string, GlobalValue*>::iterator EGV = + GlobalsByName.find(SGV->getName()); + if (EGV != GlobalsByName.end()) + DGV = dyn_cast<GlobalVariable>(EGV->second); + if (DGV) + // If types don't agree due to opaque types, try to resolve them. + RecursiveResolveTypes(SGV->getType(), DGV->getType(),ST, ""); + } + + if (DGV && DGV->hasInternalLinkage()) + DGV = 0; + + assert(SGV->hasInitializer() || SGV->hasExternalLinkage() && + "Global must either be external or have an initializer!"); + + GlobalValue::LinkageTypes NewLinkage; + bool LinkFromSrc; + if (GetLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc, Err)) + return true; + + if (!DGV) { + // No linking to be performed, simply create an identical version of the + // symbol over in the dest module... the initializer will be filled in + // later by LinkGlobalInits... + GlobalVariable *NewDGV = + new GlobalVariable(SGV->getType()->getElementType(), + SGV->isConstant(), SGV->getLinkage(), /*init*/0, + SGV->getName(), Dest); + + // If the LLVM runtime renamed the global, but it is an externally visible + // symbol, DGV must be an existing global with internal linkage. Rename + // it. + if (NewDGV->getName() != SGV->getName() && !NewDGV->hasInternalLinkage()) + ForceRenaming(NewDGV, SGV->getName()); + + // Make sure to remember this mapping... + ValueMap.insert(std::make_pair(SGV, NewDGV)); + if (SGV->hasAppendingLinkage()) + // Keep track that this is an appending variable... + AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); + } else if (DGV->hasAppendingLinkage()) { + // No linking is performed yet. Just insert a new copy of the global, and + // keep track of the fact that it is an appending variable in the + // AppendingVars map. The name is cleared out so that no linkage is + // performed. + GlobalVariable *NewDGV = + new GlobalVariable(SGV->getType()->getElementType(), + SGV->isConstant(), SGV->getLinkage(), /*init*/0, + "", Dest); + + // Make sure to remember this mapping... + ValueMap.insert(std::make_pair(SGV, NewDGV)); + + // Keep track that this is an appending variable... + AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV)); + } else { + // Otherwise, perform the mapping as instructed by GetLinkageResult. If + // the types don't match, and if we are to link from the source, nuke DGV + // and create a new one of the appropriate type. + if (SGV->getType() != DGV->getType() && LinkFromSrc) { + GlobalVariable *NewDGV = + new GlobalVariable(SGV->getType()->getElementType(), + DGV->isConstant(), DGV->getLinkage()); + Dest->getGlobalList().insert(DGV, NewDGV); + DGV->replaceAllUsesWith(ConstantExpr::getCast(NewDGV, DGV->getType())); + DGV->eraseFromParent(); + NewDGV->setName(SGV->getName()); + DGV = NewDGV; + } + + DGV->setLinkage(NewLinkage); + + if (LinkFromSrc) { + // Inherit const as appropriate + DGV->setConstant(SGV->isConstant()); + DGV->setInitializer(0); + } else { + if (SGV->isConstant() && !DGV->isConstant()) { + if (DGV->isExternal()) + DGV->setConstant(true); + } + SGV->setLinkage(GlobalValue::ExternalLinkage); + SGV->setInitializer(0); + } + + ValueMap.insert(std::make_pair(SGV, + ConstantExpr::getCast(DGV, + SGV->getType()))); + } + } + return false; +} + + +// LinkGlobalInits - Update the initializers in the Dest module now that all +// globals that may be referenced are in Dest. +static bool LinkGlobalInits(Module *Dest, const Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::string *Err) { + + // Loop over all of the globals in the src module, mapping them over as we go + for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end(); I != E; ++I){ + const GlobalVariable *SGV = I; + + if (SGV->hasInitializer()) { // Only process initialized GV's + // Figure out what the initializer looks like in the dest module... + Constant *SInit = + cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap)); + + GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]); + if (DGV->hasInitializer()) { + if (SGV->hasExternalLinkage()) { + if (DGV->getInitializer() != SInit) + return Error(Err, "Global Variable Collision on '" + + ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+ + " - Global variables have different initializers"); + } else if (DGV->hasLinkOnceLinkage() || DGV->hasWeakLinkage()) { + // Nothing is required, mapped values will take the new global + // automatically. + } else if (SGV->hasLinkOnceLinkage() || SGV->hasWeakLinkage()) { + // Nothing is required, mapped values will take the new global + // automatically. + } else if (DGV->hasAppendingLinkage()) { + assert(0 && "Appending linkage unimplemented!"); + } else { + assert(0 && "Unknown linkage!"); + } + } else { + // Copy the initializer over now... + DGV->setInitializer(SInit); + } + } + } + return false; +} + +// LinkFunctionProtos - Link the functions together between the two modules, +// without doing function bodies... this just adds external function prototypes +// to the Dest function... +// +static bool LinkFunctionProtos(Module *Dest, const Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::map<std::string, GlobalValue*> &GlobalsByName, + std::string *Err) { + SymbolTable *ST = (SymbolTable*)&Dest->getSymbolTable(); + + // Loop over all of the functions in the src module, mapping them over as we + // go + for (Module::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) { + const Function *SF = I; // SrcFunction + Function *DF = 0; + if (SF->hasName() && !SF->hasInternalLinkage()) { + // Check to see if may have to link the function. + if (!(DF = Dest->getFunction(SF->getName(), SF->getFunctionType()))) { + std::map<std::string, GlobalValue*>::iterator EF = + GlobalsByName.find(SF->getName()); + if (EF != GlobalsByName.end()) + DF = dyn_cast<Function>(EF->second); + if (DF && RecursiveResolveTypes(SF->getType(), DF->getType(), ST, "")) + DF = 0; // FIXME: gross. + } + } + + if (!DF || SF->hasInternalLinkage() || DF->hasInternalLinkage()) { + // Function does not already exist, simply insert an function signature + // identical to SF into the dest module... + Function *NewDF = new Function(SF->getFunctionType(), SF->getLinkage(), + SF->getName(), Dest); + NewDF->setCallingConv(SF->getCallingConv()); + + // If the LLVM runtime renamed the function, but it is an externally + // visible symbol, DF must be an existing function with internal linkage. + // Rename it. + if (NewDF->getName() != SF->getName() && !NewDF->hasInternalLinkage()) + ForceRenaming(NewDF, SF->getName()); + + // ... and remember this mapping... + ValueMap.insert(std::make_pair(SF, NewDF)); + } else if (SF->isExternal()) { + // If SF is external or if both SF & DF are external.. Just link the + // external functions, we aren't adding anything. + ValueMap.insert(std::make_pair(SF, DF)); + } else if (DF->isExternal()) { // If DF is external but SF is not... + // Link the external functions, update linkage qualifiers + ValueMap.insert(std::make_pair(SF, DF)); + DF->setLinkage(SF->getLinkage()); + + } else if (SF->hasWeakLinkage() || SF->hasLinkOnceLinkage()) { + // At this point we know that DF has LinkOnce, Weak, or External linkage. + ValueMap.insert(std::make_pair(SF, DF)); + + // Linkonce+Weak = Weak + if (DF->hasLinkOnceLinkage() && SF->hasWeakLinkage()) + DF->setLinkage(SF->getLinkage()); + + } else if (DF->hasWeakLinkage() || DF->hasLinkOnceLinkage()) { + // At this point we know that SF has LinkOnce or External linkage. + ValueMap.insert(std::make_pair(SF, DF)); + if (!SF->hasLinkOnceLinkage()) // Don't inherit linkonce linkage + DF->setLinkage(SF->getLinkage()); + + } else if (SF->getLinkage() != DF->getLinkage()) { + return Error(Err, "Functions named '" + SF->getName() + + "' have different linkage specifiers!"); + } else if (SF->hasExternalLinkage()) { + // The function is defined in both modules!! + return Error(Err, "Function '" + + ToStr(SF->getFunctionType(), Src) + "':\"" + + SF->getName() + "\" - Function is already defined!"); + } else { + assert(0 && "Unknown linkage configuration found!"); + } + } + return false; +} + +// LinkFunctionBody - Copy the source function over into the dest function and +// fix up references to values. At this point we know that Dest is an external +// function, and that Src is not. +static bool LinkFunctionBody(Function *Dest, Function *Src, + std::map<const Value*, Value*> &GlobalMap, + std::string *Err) { + assert(Src && Dest && Dest->isExternal() && !Src->isExternal()); + + // Go through and convert function arguments over, remembering the mapping. + Function::arg_iterator DI = Dest->arg_begin(); + for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); + I != E; ++I, ++DI) { + DI->setName(I->getName()); // Copy the name information over... + + // Add a mapping to our local map + GlobalMap.insert(std::make_pair(I, DI)); + } + + // Splice the body of the source function into the dest function. + Dest->getBasicBlockList().splice(Dest->end(), Src->getBasicBlockList()); + + // At this point, all of the instructions and values of the function are now + // copied over. The only problem is that they are still referencing values in + // the Source function as operands. Loop through all of the operands of the + // functions and patch them up to point to the local versions... + // + for (Function::iterator BB = Dest->begin(), BE = Dest->end(); BB != BE; ++BB) + for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) + for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end(); + OI != OE; ++OI) + if (!isa<Instruction>(*OI) && !isa<BasicBlock>(*OI)) + *OI = RemapOperand(*OI, GlobalMap); + + // There is no need to map the arguments anymore. + for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); I != E; ++I) + GlobalMap.erase(I); + + return false; +} + + +// LinkFunctionBodies - Link in the function bodies that are defined in the +// source module into the DestModule. This consists basically of copying the +// function over and fixing up references to values. +static bool LinkFunctionBodies(Module *Dest, Module *Src, + std::map<const Value*, Value*> &ValueMap, + std::string *Err) { + + // Loop over all of the functions in the src module, mapping them over as we + // go + for (Module::iterator SF = Src->begin(), E = Src->end(); SF != E; ++SF) { + if (!SF->isExternal()) { // No body if function is external + Function *DF = cast<Function>(ValueMap[SF]); // Destination function + + // DF not external SF external? + if (DF->isExternal()) { + // Only provide the function body if there isn't one already. + if (LinkFunctionBody(DF, SF, ValueMap, Err)) + return true; + } + } + } + return false; +} + +// LinkAppendingVars - If there were any appending global variables, link them +// together now. Return true on error. +static bool LinkAppendingVars(Module *M, + std::multimap<std::string, GlobalVariable *> &AppendingVars, + std::string *ErrorMsg) { + if (AppendingVars.empty()) return false; // Nothing to do. + + // Loop over the multimap of appending vars, processing any variables with the + // same name, forming a new appending global variable with both of the + // initializers merged together, then rewrite references to the old variables + // and delete them. + std::vector<Constant*> Inits; + while (AppendingVars.size() > 1) { + // Get the first two elements in the map... + std::multimap<std::string, + GlobalVariable*>::iterator Second = AppendingVars.begin(), First=Second++; + + // If the first two elements are for different names, there is no pair... + // Otherwise there is a pair, so link them together... + if (First->first == Second->first) { + GlobalVariable *G1 = First->second, *G2 = Second->second; + const ArrayType *T1 = cast<ArrayType>(G1->getType()->getElementType()); + const ArrayType *T2 = cast<ArrayType>(G2->getType()->getElementType()); + + // Check to see that they two arrays agree on type... + if (T1->getElementType() != T2->getElementType()) + return Error(ErrorMsg, + "Appending variables with different element types need to be linked!"); + if (G1->isConstant() != G2->isConstant()) + return Error(ErrorMsg, + "Appending variables linked with different const'ness!"); + + unsigned NewSize = T1->getNumElements() + T2->getNumElements(); + ArrayType *NewType = ArrayType::get(T1->getElementType(), NewSize); + + // Create the new global variable... + GlobalVariable *NG = + new GlobalVariable(NewType, G1->isConstant(), G1->getLinkage(), + /*init*/0, First->first, M); + + // Merge the initializer... + Inits.reserve(NewSize); + if (ConstantArray *I = dyn_cast<ConstantArray>(G1->getInitializer())) { + for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) + Inits.push_back(I->getOperand(i)); + } else { + assert(isa<ConstantAggregateZero>(G1->getInitializer())); + Constant *CV = Constant::getNullValue(T1->getElementType()); + for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i) + Inits.push_back(CV); + } + if (ConstantArray *I = dyn_cast<ConstantArray>(G2->getInitializer())) { + for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) + Inits.push_back(I->getOperand(i)); + } else { + assert(isa<ConstantAggregateZero>(G2->getInitializer())); + Constant *CV = Constant::getNullValue(T2->getElementType()); + for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i) + Inits.push_back(CV); + } + NG->setInitializer(ConstantArray::get(NewType, Inits)); + Inits.clear(); + + // Replace any uses of the two global variables with uses of the new + // global... + + // FIXME: This should rewrite simple/straight-forward uses such as + // getelementptr instructions to not use the Cast! + G1->replaceAllUsesWith(ConstantExpr::getCast(NG, G1->getType())); + G2->replaceAllUsesWith(ConstantExpr::getCast(NG, G2->getType())); + + // Remove the two globals from the module now... + M->getGlobalList().erase(G1); + M->getGlobalList().erase(G2); + + // Put the new global into the AppendingVars map so that we can handle + // linking of more than two vars... + Second->second = NG; + } + AppendingVars.erase(First); + } + + return false; +} + + +// LinkModules - This function links two modules together, with the resulting +// left module modified to be the composite of the two input modules. If an +// error occurs, true is returned and ErrorMsg (if not null) is set to indicate +// the problem. Upon failure, the Dest module could be in a modified state, and +// shouldn't be relied on to be consistent. +bool +Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { + assert(Dest != 0 && "Invalid Destination module"); + assert(Src != 0 && "Invalid Source Module"); + + if (Dest->getEndianness() == Module::AnyEndianness) + Dest->setEndianness(Src->getEndianness()); + if (Dest->getPointerSize() == Module::AnyPointerSize) + Dest->setPointerSize(Src->getPointerSize()); + if (Dest->getTargetTriple().empty()) + Dest->setTargetTriple(Src->getTargetTriple()); + + if (Src->getEndianness() != Module::AnyEndianness && + Dest->getEndianness() != Src->getEndianness()) + std::cerr << "WARNING: Linking two modules of different endianness!\n"; + if (Src->getPointerSize() != Module::AnyPointerSize && + Dest->getPointerSize() != Src->getPointerSize()) + std::cerr << "WARNING: Linking two modules of different pointer size!\n"; + if (!Src->getTargetTriple().empty() && + Dest->getTargetTriple() != Src->getTargetTriple()) + std::cerr << "WARNING: Linking two modules of different target triples!\n"; + + // Update the destination module's dependent libraries list with the libraries + // from the source module. There's no opportunity for duplicates here as the + // Module ensures that duplicate insertions are discarded. + Module::lib_iterator SI = Src->lib_begin(); + Module::lib_iterator SE = Src->lib_end(); + while ( SI != SE ) { + Dest->addLibrary(*SI); + ++SI; + } + + // LinkTypes - Go through the symbol table of the Src module and see if any + // types are named in the src module that are not named in the Dst module. + // Make sure there are no type name conflicts. + if (LinkTypes(Dest, Src, ErrorMsg)) return true; + + // ValueMap - Mapping of values from what they used to be in Src, to what they + // are now in Dest. + std::map<const Value*, Value*> ValueMap; + + // AppendingVars - Keep track of global variables in the destination module + // with appending linkage. After the module is linked together, they are + // appended and the module is rewritten. + std::multimap<std::string, GlobalVariable *> AppendingVars; + + // GlobalsByName - The LLVM SymbolTable class fights our best efforts at + // linking by separating globals by type. Until PR411 is fixed, we replicate + // it's functionality here. + std::map<std::string, GlobalValue*> GlobalsByName; + + for (Module::global_iterator I = Dest->global_begin(), E = Dest->global_end(); I != E; ++I) { + // Add all of the appending globals already in the Dest module to + // AppendingVars. + if (I->hasAppendingLinkage()) + AppendingVars.insert(std::make_pair(I->getName(), I)); + + // Keep track of all globals by name. + if (!I->hasInternalLinkage() && I->hasName()) + GlobalsByName[I->getName()] = I; + } + + // Keep track of all globals by name. + for (Module::iterator I = Dest->begin(), E = Dest->end(); I != E; ++I) + if (!I->hasInternalLinkage() && I->hasName()) + GlobalsByName[I->getName()] = I; + + // Insert all of the globals in src into the Dest module... without linking + // initializers (which could refer to functions not yet mapped over). + if (LinkGlobals(Dest, Src, ValueMap, AppendingVars, GlobalsByName, ErrorMsg)) + return true; + + // Link the functions together between the two modules, without doing function + // bodies... this just adds external function prototypes to the Dest + // function... We do this so that when we begin processing function bodies, + // all of the global values that may be referenced are available in our + // ValueMap. + if (LinkFunctionProtos(Dest, Src, ValueMap, GlobalsByName, ErrorMsg)) + return true; + + // Update the initializers in the Dest module now that all globals that may + // be referenced are in Dest. + if (LinkGlobalInits(Dest, Src, ValueMap, ErrorMsg)) return true; + + // Link in the function bodies that are defined in the source module into the + // DestModule. This consists basically of copying the function over and + // fixing up references to values. + if (LinkFunctionBodies(Dest, Src, ValueMap, ErrorMsg)) return true; + + // If there were any appending global variables, link them together now. + if (LinkAppendingVars(Dest, AppendingVars, ErrorMsg)) return true; + + // If the source library's module id is in the dependent library list of the + // destination library, remove it since that module is now linked in. + sys::Path modId; + modId.set(Src->getModuleIdentifier()); + if (!modId.isEmpty()) + Dest->removeLibrary(modId.getBasename()); + + return false; +} + +// vim: sw=2 |