LinkModules.cpp revision 1bcbf8582e94eee6f151e5e2db2d04f417abf5f7
1ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===// 2ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com// 3ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com// The LLVM Compiler Infrastructure 4ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com// 5ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com// This file is distributed under the University of Illinois Open Source 6ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com// License. See LICENSE.TXT for details. 7ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com// 8ec3ed6a5ebf6f2c406d7bcf94b6bc34fcaeb976eepoger@google.com//===----------------------------------------------------------------------===// 98a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com// 108a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com// This file implements the LLVM module linker. 118a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com// 128a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com//===----------------------------------------------------------------------===// 138a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 148a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com#include "llvm/Linker.h" 158a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com#include "llvm/Constants.h" 168a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com#include "llvm/DerivedTypes.h" 178a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com#include "llvm/Module.h" 188a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com#include "llvm/Support/raw_ostream.h" 198a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com#include "llvm/Support/Path.h" 208a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com#include "llvm/Transforms/Utils/ValueMapper.h" 218a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.comusing namespace llvm; 228a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 238a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com//===----------------------------------------------------------------------===// 248a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com// TypeMap implementation. 258a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com//===----------------------------------------------------------------------===// 268a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 278a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.comnamespace { 288a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.comclass TypeMapTy : public ValueMapTypeRemapper { 298a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// MappedTypes - This is a mapping from a source type to a destination type 308a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// to use. 318a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com DenseMap<Type*, Type*> MappedTypes; 328a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 338a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// SpeculativeTypes - When checking to see if two subgraphs are isomorphic, 348a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// we speculatively add types to MappedTypes, but keep track of them here in 358a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// case we need to roll back. 368a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SmallVector<Type*, 16> SpeculativeTypes; 378a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 388a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// DefinitionsToResolve - This is a list of non-opaque structs in the source 398a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// module that are mapped to an opaque struct in the destination module. 408a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SmallVector<StructType*, 16> DefinitionsToResolve; 418a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.compublic: 428a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 438a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// addTypeMapping - Indicate that the specified type in the destination 448a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// module is conceptually equivalent to the specified type in the source 458a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// module. 468a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com void addTypeMapping(Type *DstTy, Type *SrcTy); 478a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 488a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 498a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// module from a type definition in the source module. 508a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com void linkDefinedTypeBodies(); 518a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 528a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// get - Return the mapped type to use for the specified input type from the 538a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// source module. 548a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Type *get(Type *SrcTy); 558a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 568a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));} 578a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 588a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.comprivate: 598a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Type *getImpl(Type *T); 608a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com /// remapType - Implement the ValueMapTypeRemapper interface. 618a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Type *remapType(Type *SrcTy) { 628a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return get(SrcTy); 638a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 648a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 658a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com bool areTypesIsomorphic(Type *DstTy, Type *SrcTy); 668a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com}; 678a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com} 688a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 698a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.comvoid TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) { 708a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Type *&Entry = MappedTypes[SrcTy]; 718a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (Entry) return; 728a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 738a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (DstTy == SrcTy) { 748a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Entry = DstTy; 758a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return; 768a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 778a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 788a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Check to see if these types are recursively isomorphic and establish a 798a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // mapping between them if so. 808a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (!areTypesIsomorphic(DstTy, SrcTy)) { 818a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Oops, they aren't isomorphic. Just discard this request by rolling out 828a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // any speculative mappings we've established. 838a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i) 848a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com MappedTypes.erase(SpeculativeTypes[i]); 858a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 868a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SpeculativeTypes.clear(); 878a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com} 888a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 898a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com/// areTypesIsomorphic - Recursively walk this pair of types, returning true 908a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com/// if they are isomorphic, false if they are not. 918a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.combool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) { 928a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Two types with differing kinds are clearly not isomorphic. 938a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (DstTy->getTypeID() != SrcTy->getTypeID()) return false; 948a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 958a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // If we have an entry in the MappedTypes table, then we have our answer. 968a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Type *&Entry = MappedTypes[SrcTy]; 978a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (Entry) 988a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return Entry == DstTy; 998a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1008a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Two identical types are clearly isomorphic. Remember this 1018a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // non-speculatively. 102d6176b0dcacb124539e0cfd051e6d93a9782f020rmistry@google.com if (DstTy == SrcTy) { 1038a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Entry = DstTy; 1048a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return true; 1058a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 1068a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1078a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Okay, we have two types with identical kinds that we haven't seen before. 1088a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 10964cc579efa7e416c7298ed159d76b074b283c0f9senorblanco@chromium.org // If this is an opaque struct type, special case it. 1108a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) { 1118a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Mapping an opaque type to any struct, just keep the dest struct. 1128a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (SSTy->isOpaque()) { 1138a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Entry = DstTy; 1148a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SpeculativeTypes.push_back(SrcTy); 1158a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return true; 1168a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 1178a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1188a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Mapping a non-opaque source type to an opaque dest. Keep the dest, but 1198a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // fill it in later. This doesn't need to be speculative. 1208a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (cast<StructType>(DstTy)->isOpaque()) { 1218a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Entry = DstTy; 1228a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com DefinitionsToResolve.push_back(SSTy); 1238a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return true; 1248a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 1258a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 1268a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 12764cc579efa7e416c7298ed159d76b074b283c0f9senorblanco@chromium.org // If the number of subtypes disagree between the two types, then we fail. 1288a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes()) 12964cc579efa7e416c7298ed159d76b074b283c0f9senorblanco@chromium.org return false; 1308a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1318a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Fail if any of the extra properties (e.g. array size) of the type disagree. 1328a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (isa<IntegerType>(DstTy)) 1338a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return false; // bitwidth disagrees. 1348a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (PointerType *PT = dyn_cast<PointerType>(DstTy)) { 1358a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace()) 1368a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return false; 1378a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) { 138d6176b0dcacb124539e0cfd051e6d93a9782f020rmistry@google.com if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg()) 1398a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return false; 1408a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) { 1418a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com StructType *SSTy = cast<StructType>(SrcTy); 1428a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (DSTy->isLiteral() != SSTy->isLiteral() || 1438a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com DSTy->isPacked() != SSTy->isPacked()) 1448a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return false; 1458a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) { 1468a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 1478a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return false; 1488a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) { 1498a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements()) 1508a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return false; 1518a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com } 1528a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1538a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Otherwise, we speculate that these two types will line up and recursively 1548a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // check the subelements. 1558a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Entry = DstTy; 1568a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SpeculativeTypes.push_back(SrcTy); 1578a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1588a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i) 1598a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (!areTypesIsomorphic(DstTy->getContainedType(i), 1608a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SrcTy->getContainedType(i))) 1618a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return false; 1628a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1638a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // If everything seems to have lined up, then everything is great. 1648a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com return true; 1658a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com} 1668a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1678a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest 1688a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com/// module from a type definition in the source module. 1698a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.comvoid TypeMapTy::linkDefinedTypeBodies() { 1708a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SmallVector<Type*, 16> Elements; 1718a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SmallString<16> TmpName; 1728a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1738a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Note that processing entries in this loop (calling 'get') can add new 1748a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // entries to the DefinitionsToResolve vector. 17564cc579efa7e416c7298ed159d76b074b283c0f9senorblanco@chromium.org while (!DefinitionsToResolve.empty()) { 1768a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com StructType *SrcSTy = DefinitionsToResolve.pop_back_val(); 1778a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]); 1788a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1798a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // TypeMap is a many-to-one mapping, if there were multiple types that 1808a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // provide a body for DstSTy then previous iterations of this loop may have 1818a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // already handled it. Just ignore this case. 1828a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (!DstSTy->isOpaque()) continue; 1838a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com assert(!SrcSTy->isOpaque() && "Not resolving a definition?"); 1848a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1858a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // Map the body of the source type over to a new body for the dest type. 1868a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Elements.resize(SrcSTy->getNumElements()); 1878a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com for (unsigned i = 0, e = Elements.size(); i != e; ++i) 1888a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Elements[i] = getImpl(SrcSTy->getElementType(i)); 1898a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1908a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com DstSTy->setBody(Elements, SrcSTy->isPacked()); 1918a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1928a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // If DstSTy has no name or has a longer name than STy, then viciously steal 1938a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com // STy's name. 1948a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (!SrcSTy->hasName()) continue; 1958a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com StringRef SrcName = SrcSTy->getName(); 1968a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 1978a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) { 1988a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end()); 1998a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com SrcSTy->setName(""); 2008a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com DstSTy->setName(TmpName.str()); 2018a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com TmpName.clear(); 20264cc579efa7e416c7298ed159d76b074b283c0f9senorblanco@chromium.org } 20364cc579efa7e416c7298ed159d76b074b283c0f9senorblanco@chromium.org } 2048a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com} 2058a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 2068a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 2078a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com/// get - Return the mapped type to use for the specified input type from the 2088a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com/// source module. 2098a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.comType *TypeMapTy::get(Type *Ty) { 2108a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com Type *Result = getImpl(Ty); 2118a1c16ff38322f0210116fa7293eb8817c7e477ereed@android.com 212 // If this caused a reference to any struct type, resolve it before returning. 213 if (!DefinitionsToResolve.empty()) 214 linkDefinedTypeBodies(); 215 return Result; 216} 217 218/// getImpl - This is the recursive version of get(). 219Type *TypeMapTy::getImpl(Type *Ty) { 220 // If we already have an entry for this type, return it. 221 Type **Entry = &MappedTypes[Ty]; 222 if (*Entry) return *Entry; 223 224 // If this is not a named struct type, then just map all of the elements and 225 // then rebuild the type from inside out. 226 if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) { 227 // If there are no element types to map, then the type is itself. This is 228 // true for the anonymous {} struct, things like 'float', integers, etc. 229 if (Ty->getNumContainedTypes() == 0) 230 return *Entry = Ty; 231 232 // Remap all of the elements, keeping track of whether any of them change. 233 bool AnyChange = false; 234 SmallVector<Type*, 4> ElementTypes; 235 ElementTypes.resize(Ty->getNumContainedTypes()); 236 for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) { 237 ElementTypes[i] = getImpl(Ty->getContainedType(i)); 238 AnyChange |= ElementTypes[i] != Ty->getContainedType(i); 239 } 240 241 // If we found our type while recursively processing stuff, just use it. 242 Entry = &MappedTypes[Ty]; 243 if (*Entry) return *Entry; 244 245 // If all of the element types mapped directly over, then the type is usable 246 // as-is. 247 if (!AnyChange) 248 return *Entry = Ty; 249 250 // Otherwise, rebuild a modified type. 251 switch (Ty->getTypeID()) { 252 default: assert(0 && "unknown derived type to remap"); 253 case Type::ArrayTyID: 254 return *Entry = ArrayType::get(ElementTypes[0], 255 cast<ArrayType>(Ty)->getNumElements()); 256 case Type::VectorTyID: 257 return *Entry = VectorType::get(ElementTypes[0], 258 cast<VectorType>(Ty)->getNumElements()); 259 case Type::PointerTyID: 260 return *Entry = PointerType::get(ElementTypes[0], 261 cast<PointerType>(Ty)->getAddressSpace()); 262 case Type::FunctionTyID: 263 return *Entry = FunctionType::get(ElementTypes[0], 264 makeArrayRef(ElementTypes).slice(1), 265 cast<FunctionType>(Ty)->isVarArg()); 266 case Type::StructTyID: 267 // Note that this is only reached for anonymous structs. 268 return *Entry = StructType::get(Ty->getContext(), ElementTypes, 269 cast<StructType>(Ty)->isPacked()); 270 } 271 } 272 273 // Otherwise, this is an unmapped named struct. If the struct can be directly 274 // mapped over, just use it as-is. This happens in a case when the linked-in 275 // module has something like: 276 // %T = type {%T*, i32} 277 // @GV = global %T* null 278 // where T does not exist at all in the destination module. 279 // 280 // The other case we watch for is when the type is not in the destination 281 // module, but that it has to be rebuilt because it refers to something that 282 // is already mapped. For example, if the destination module has: 283 // %A = type { i32 } 284 // and the source module has something like 285 // %A' = type { i32 } 286 // %B = type { %A'* } 287 // @GV = global %B* null 288 // then we want to create a new type: "%B = type { %A*}" and have it take the 289 // pristine "%B" name from the source module. 290 // 291 // To determine which case this is, we have to recursively walk the type graph 292 // speculating that we'll be able to reuse it unmodified. Only if this is 293 // safe would we map the entire thing over. Because this is an optimization, 294 // and is not required for the prettiness of the linked module, we just skip 295 // it and always rebuild a type here. 296 StructType *STy = cast<StructType>(Ty); 297 298 // If the type is opaque, we can just use it directly. 299 if (STy->isOpaque()) 300 return *Entry = STy; 301 302 // Otherwise we create a new type and resolve its body later. This will be 303 // resolved by the top level of get(). 304 DefinitionsToResolve.push_back(STy); 305 return *Entry = StructType::create(STy->getContext()); 306} 307 308 309 310//===----------------------------------------------------------------------===// 311// ModuleLinker implementation. 312//===----------------------------------------------------------------------===// 313 314namespace { 315 /// ModuleLinker - This is an implementation class for the LinkModules 316 /// function, which is the entrypoint for this file. 317 class ModuleLinker { 318 Module *DstM, *SrcM; 319 320 TypeMapTy TypeMap; 321 322 /// ValueMap - Mapping of values from what they used to be in Src, to what 323 /// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves 324 /// some overhead due to the use of Value handles which the Linker doesn't 325 /// actually need, but this allows us to reuse the ValueMapper code. 326 ValueToValueMapTy ValueMap; 327 328 struct AppendingVarInfo { 329 GlobalVariable *NewGV; // New aggregate global in dest module. 330 Constant *DstInit; // Old initializer from dest module. 331 Constant *SrcInit; // Old initializer from src module. 332 }; 333 334 std::vector<AppendingVarInfo> AppendingVars; 335 336 public: 337 std::string ErrorMsg; 338 339 ModuleLinker(Module *dstM, Module *srcM) : DstM(dstM), SrcM(srcM) { } 340 341 bool run(); 342 343 private: 344 /// emitError - Helper method for setting a message and returning an error 345 /// code. 346 bool emitError(const Twine &Message) { 347 ErrorMsg = Message.str(); 348 return true; 349 } 350 351 /// getLinkageResult - This analyzes the two global values and determines 352 /// what the result will look like in the destination module. 353 bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 354 GlobalValue::LinkageTypes <, bool &LinkFromSrc); 355 356 /// getLinkedToGlobal - Given a global in the source module, return the 357 /// global in the destination module that is being linked to, if any. 358 GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) { 359 // If the source has no name it can't link. If it has local linkage, 360 // there is no name match-up going on. 361 if (!SrcGV->hasName() || SrcGV->hasLocalLinkage()) 362 return 0; 363 364 // Otherwise see if we have a match in the destination module's symtab. 365 GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName()); 366 if (DGV == 0) return 0; 367 368 // If we found a global with the same name in the dest module, but it has 369 // internal linkage, we are really not doing any linkage here. 370 if (DGV->hasLocalLinkage()) 371 return 0; 372 373 // Otherwise, we do in fact link to the destination global. 374 return DGV; 375 } 376 377 void computeTypeMapping(); 378 379 bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV); 380 bool linkGlobalProto(GlobalVariable *SrcGV); 381 bool linkFunctionProto(Function *SrcF); 382 bool linkAliasProto(GlobalAlias *SrcA); 383 384 void linkAppendingVarInit(const AppendingVarInfo &AVI); 385 void linkGlobalInits(); 386 void linkFunctionBody(Function *Dst, Function *Src); 387 void linkAliasBodies(); 388 void linkNamedMDNodes(); 389 }; 390} 391 392 393 394/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict 395/// in the symbol table. This is good for all clients except for us. Go 396/// through the trouble to force this back. 397static void forceRenaming(GlobalValue *GV, StringRef Name) { 398 // If the global doesn't force its name or if it already has the right name, 399 // there is nothing for us to do. 400 if (GV->hasLocalLinkage() || GV->getName() == Name) 401 return; 402 403 Module *M = GV->getParent(); 404 405 // If there is a conflict, rename the conflict. 406 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) { 407 GV->takeName(ConflictGV); 408 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed 409 assert(ConflictGV->getName() != Name && "forceRenaming didn't work"); 410 } else { 411 GV->setName(Name); // Force the name back 412 } 413} 414 415/// CopyGVAttributes - copy additional attributes (those not needed to construct 416/// a GlobalValue) from the SrcGV to the DestGV. 417static void CopyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) { 418 // Use the maximum alignment, rather than just copying the alignment of SrcGV. 419 unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment()); 420 DestGV->copyAttributesFrom(SrcGV); 421 DestGV->setAlignment(Alignment); 422 423 forceRenaming(DestGV, SrcGV->getName()); 424} 425 426/// getLinkageResult - This analyzes the two global values and determines what 427/// the result will look like in the destination module. In particular, it 428/// computes the resultant linkage type, computes whether the global in the 429/// source should be copied over to the destination (replacing the existing 430/// one), and computes whether this linkage is an error or not. It also performs 431/// visibility checks: we cannot link together two symbols with different 432/// visibilities. 433bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src, 434 GlobalValue::LinkageTypes <, 435 bool &LinkFromSrc) { 436 assert(Dest && "Must have two globals being queried"); 437 assert(!Src->hasLocalLinkage() && 438 "If Src has internal linkage, Dest shouldn't be set!"); 439 440 bool SrcIsDeclaration = Src->isDeclaration(); 441 bool DestIsDeclaration = Dest->isDeclaration(); 442 443 if (SrcIsDeclaration) { 444 // If Src is external or if both Src & Dest are external.. Just link the 445 // external globals, we aren't adding anything. 446 if (Src->hasDLLImportLinkage()) { 447 // If one of GVs has DLLImport linkage, result should be dllimport'ed. 448 if (DestIsDeclaration) { 449 LinkFromSrc = true; 450 LT = Src->getLinkage(); 451 } 452 } else if (Dest->hasExternalWeakLinkage()) { 453 // If the Dest is weak, use the source linkage. 454 LinkFromSrc = true; 455 LT = Src->getLinkage(); 456 } else { 457 LinkFromSrc = false; 458 LT = Dest->getLinkage(); 459 } 460 } else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) { 461 // If Dest is external but Src is not: 462 LinkFromSrc = true; 463 LT = Src->getLinkage(); 464 } else if (Src->isWeakForLinker()) { 465 // At this point we know that Dest has LinkOnce, External*, Weak, Common, 466 // or DLL* linkage. 467 if (Dest->hasExternalWeakLinkage() || 468 Dest->hasAvailableExternallyLinkage() || 469 (Dest->hasLinkOnceLinkage() && 470 (Src->hasWeakLinkage() || Src->hasCommonLinkage()))) { 471 LinkFromSrc = true; 472 LT = Src->getLinkage(); 473 } else { 474 LinkFromSrc = false; 475 LT = Dest->getLinkage(); 476 } 477 } else if (Dest->isWeakForLinker()) { 478 // At this point we know that Src has External* or DLL* linkage. 479 if (Src->hasExternalWeakLinkage()) { 480 LinkFromSrc = false; 481 LT = Dest->getLinkage(); 482 } else { 483 LinkFromSrc = true; 484 LT = GlobalValue::ExternalLinkage; 485 } 486 } else { 487 assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() || 488 Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) && 489 (Src->hasExternalLinkage() || Src->hasDLLImportLinkage() || 490 Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) && 491 "Unexpected linkage type!"); 492 return emitError("Linking globals named '" + Src->getName() + 493 "': symbol multiply defined!"); 494 } 495 496 // Check visibility 497 if (Src->getVisibility() != Dest->getVisibility() && 498 !SrcIsDeclaration && !DestIsDeclaration && 499 !Src->hasAvailableExternallyLinkage() && 500 !Dest->hasAvailableExternallyLinkage()) 501 return emitError("Linking globals named '" + Src->getName() + 502 "': symbols have different visibilities!"); 503 return false; 504} 505 506/// computeTypeMapping - Loop over all of the linked values to compute type 507/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then 508/// we have two struct types 'Foo' but one got renamed when the module was 509/// loaded into the same LLVMContext. 510void ModuleLinker::computeTypeMapping() { 511 // Incorporate globals. 512 for (Module::global_iterator I = SrcM->global_begin(), 513 E = SrcM->global_end(); I != E; ++I) { 514 GlobalValue *DGV = getLinkedToGlobal(I); 515 if (DGV == 0) continue; 516 517 if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) { 518 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 519 continue; 520 } 521 522 // Unify the element type of appending arrays. 523 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType()); 524 ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType()); 525 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType()); 526 } 527 528 // Incorporate functions. 529 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) { 530 if (GlobalValue *DGV = getLinkedToGlobal(I)) 531 TypeMap.addTypeMapping(DGV->getType(), I->getType()); 532 } 533 534 // Don't bother incorporating aliases, they aren't generally typed well. 535 536 // Now that we have discovered all of the type equivalences, get a body for 537 // any 'opaque' types in the dest module that are now resolved. 538 TypeMap.linkDefinedTypeBodies(); 539} 540 541/// linkAppendingVarProto - If there were any appending global variables, link 542/// them together now. Return true on error. 543bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV, 544 GlobalVariable *SrcGV) { 545 546 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage()) 547 return emitError("Linking globals named '" + SrcGV->getName() + 548 "': can only link appending global with another appending global!"); 549 550 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType()); 551 ArrayType *SrcTy = 552 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType())); 553 Type *EltTy = DstTy->getElementType(); 554 555 // Check to see that they two arrays agree on type. 556 if (EltTy != SrcTy->getElementType()) 557 return emitError("Appending variables with different element types!"); 558 if (DstGV->isConstant() != SrcGV->isConstant()) 559 return emitError("Appending variables linked with different const'ness!"); 560 561 if (DstGV->getAlignment() != SrcGV->getAlignment()) 562 return emitError( 563 "Appending variables with different alignment need to be linked!"); 564 565 if (DstGV->getVisibility() != SrcGV->getVisibility()) 566 return emitError( 567 "Appending variables with different visibility need to be linked!"); 568 569 if (DstGV->getSection() != SrcGV->getSection()) 570 return emitError( 571 "Appending variables with different section name need to be linked!"); 572 573 uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements(); 574 ArrayType *NewType = ArrayType::get(EltTy, NewSize); 575 576 // Create the new global variable. 577 GlobalVariable *NG = 578 new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(), 579 DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV, 580 DstGV->isThreadLocal(), 581 DstGV->getType()->getAddressSpace()); 582 583 // Propagate alignment, visibility and section info. 584 CopyGVAttributes(NG, DstGV); 585 586 AppendingVarInfo AVI; 587 AVI.NewGV = NG; 588 AVI.DstInit = DstGV->getInitializer(); 589 AVI.SrcInit = SrcGV->getInitializer(); 590 AppendingVars.push_back(AVI); 591 592 // Replace any uses of the two global variables with uses of the new 593 // global. 594 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType())); 595 596 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType())); 597 DstGV->eraseFromParent(); 598 599 // Zap the initializer in the source variable so we don't try to link it. 600 SrcGV->setInitializer(0); 601 SrcGV->setLinkage(GlobalValue::ExternalLinkage); 602 return false; 603} 604 605/// linkGlobalProto - Loop through the global variables in the src module and 606/// merge them into the dest module. 607bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) { 608 GlobalValue *DGV = getLinkedToGlobal(SGV); 609 610 if (DGV) { 611 // Concatenation of appending linkage variables is magic and handled later. 612 if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage()) 613 return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV); 614 615 // Determine whether linkage of these two globals follows the source 616 // module's definition or the destination module's definition. 617 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 618 bool LinkFromSrc = false; 619 if (getLinkageResult(DGV, SGV, NewLinkage, LinkFromSrc)) 620 return true; 621 622 // If we're not linking from the source, then keep the definition that we 623 // have. 624 if (!LinkFromSrc) { 625 // Special case for const propagation. 626 if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) 627 if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant()) 628 DGVar->setConstant(true); 629 630 // Set calculated linkage. 631 DGV->setLinkage(NewLinkage); 632 633 // Make sure to remember this mapping. 634 ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType())); 635 636 // Destroy the source global's initializer (and convert it to a prototype) 637 // so that we don't attempt to copy it over when processing global 638 // initializers. 639 SGV->setInitializer(0); 640 SGV->setLinkage(GlobalValue::ExternalLinkage); 641 return false; 642 } 643 } 644 645 // No linking to be performed or linking from the source: simply create an 646 // identical version of the symbol over in the dest module... the 647 // initializer will be filled in later by LinkGlobalInits. 648 GlobalVariable *NewDGV = 649 new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()), 650 SGV->isConstant(), SGV->getLinkage(), /*init*/0, 651 SGV->getName(), /*insertbefore*/0, 652 SGV->isThreadLocal(), 653 SGV->getType()->getAddressSpace()); 654 // Propagate alignment, visibility and section info. 655 CopyGVAttributes(NewDGV, SGV); 656 657 if (DGV) { 658 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType())); 659 DGV->eraseFromParent(); 660 } 661 662 // Make sure to remember this mapping. 663 ValueMap[SGV] = NewDGV; 664 return false; 665} 666 667/// linkFunctionProto - Link the function in the source module into the 668/// destination module if needed, setting up mapping information. 669bool ModuleLinker::linkFunctionProto(Function *SF) { 670 GlobalValue *DGV = getLinkedToGlobal(SF); 671 672 if (DGV) { 673 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 674 bool LinkFromSrc = false; 675 if (getLinkageResult(DGV, SF, NewLinkage, LinkFromSrc)) 676 return true; 677 678 if (!LinkFromSrc) { 679 // Set calculated linkage 680 DGV->setLinkage(NewLinkage); 681 682 // Make sure to remember this mapping. 683 ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType())); 684 685 // Remove the body from the source module so we don't attempt to remap it. 686 SF->deleteBody(); 687 return false; 688 } 689 } 690 691 // If there is no linkage to be performed or we are linking from the source, 692 // bring SF over. 693 Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()), 694 SF->getLinkage(), SF->getName(), DstM); 695 CopyGVAttributes(NewDF, SF); 696 697 if (DGV) { 698 // Any uses of DF need to change to NewDF, with cast. 699 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType())); 700 DGV->eraseFromParent(); 701 } 702 703 ValueMap[SF] = NewDF; 704 return false; 705} 706 707/// LinkAliasProto - Set up prototypes for any aliases that come over from the 708/// source module. 709bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) { 710 GlobalValue *DGV = getLinkedToGlobal(SGA); 711 712 if (DGV) { 713 GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage; 714 bool LinkFromSrc = false; 715 if (getLinkageResult(DGV, SGA, NewLinkage, LinkFromSrc)) 716 return true; 717 718 if (!LinkFromSrc) { 719 // Set calculated linkage. 720 DGV->setLinkage(NewLinkage); 721 722 // Make sure to remember this mapping. 723 ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType())); 724 725 // Remove the body from the source module so we don't attempt to remap it. 726 SGA->setAliasee(0); 727 return false; 728 } 729 } 730 731 // If there is no linkage to be performed or we're linking from the source, 732 // bring over SGA. 733 GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()), 734 SGA->getLinkage(), SGA->getName(), 735 /*aliasee*/0, DstM); 736 CopyGVAttributes(NewDA, SGA); 737 738 if (DGV) { 739 // Any uses of DGV need to change to NewDA, with cast. 740 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType())); 741 DGV->eraseFromParent(); 742 } 743 744 ValueMap[SGA] = NewDA; 745 return false; 746} 747 748void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) { 749 // Merge the initializer. 750 SmallVector<Constant*, 16> Elements; 751 if (ConstantArray *I = dyn_cast<ConstantArray>(AVI.DstInit)) { 752 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 753 Elements.push_back(I->getOperand(i)); 754 } else { 755 assert(isa<ConstantAggregateZero>(AVI.DstInit)); 756 ArrayType *DstAT = cast<ArrayType>(AVI.DstInit->getType()); 757 Type *EltTy = DstAT->getElementType(); 758 Elements.append(DstAT->getNumElements(), Constant::getNullValue(EltTy)); 759 } 760 761 Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap); 762 if (const ConstantArray *I = dyn_cast<ConstantArray>(SrcInit)) { 763 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 764 Elements.push_back(I->getOperand(i)); 765 } else { 766 assert(isa<ConstantAggregateZero>(SrcInit)); 767 ArrayType *SrcAT = cast<ArrayType>(SrcInit->getType()); 768 Type *EltTy = SrcAT->getElementType(); 769 Elements.append(SrcAT->getNumElements(), Constant::getNullValue(EltTy)); 770 } 771 ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType()); 772 AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements)); 773} 774 775 776// linkGlobalInits - Update the initializers in the Dest module now that all 777// globals that may be referenced are in Dest. 778void ModuleLinker::linkGlobalInits() { 779 // Loop over all of the globals in the src module, mapping them over as we go 780 for (Module::const_global_iterator I = SrcM->global_begin(), 781 E = SrcM->global_end(); I != E; ++I) { 782 if (!I->hasInitializer()) continue; // Only process initialized GV's. 783 784 // Grab destination global variable. 785 GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]); 786 // Figure out what the initializer looks like in the dest module. 787 DGV->setInitializer(MapValue(I->getInitializer(), ValueMap, 788 RF_None, &TypeMap)); 789 } 790} 791 792// linkFunctionBody - Copy the source function over into the dest function and 793// fix up references to values. At this point we know that Dest is an external 794// function, and that Src is not. 795void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) { 796 assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration()); 797 798 // Go through and convert function arguments over, remembering the mapping. 799 Function::arg_iterator DI = Dst->arg_begin(); 800 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 801 I != E; ++I, ++DI) { 802 DI->setName(I->getName()); // Copy the name over. 803 804 // Add a mapping to our mapping. 805 ValueMap[I] = DI; 806 } 807 808 // Splice the body of the source function into the dest function. 809 Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList()); 810 811 // At this point, all of the instructions and values of the function are now 812 // copied over. The only problem is that they are still referencing values in 813 // the Source function as operands. Loop through all of the operands of the 814 // functions and patch them up to point to the local versions. 815 for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB) 816 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) 817 RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap); 818 819 // There is no need to map the arguments anymore. 820 for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end(); 821 I != E; ++I) 822 ValueMap.erase(I); 823} 824 825 826void ModuleLinker::linkAliasBodies() { 827 for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end(); 828 I != E; ++I) 829 if (Constant *Aliasee = I->getAliasee()) { 830 GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]); 831 DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap)); 832 } 833} 834 835/// linkNamedMDNodes - Insert all of the named mdnodes in Src into the Dest 836/// module. 837void ModuleLinker::linkNamedMDNodes() { 838 for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(), 839 E = SrcM->named_metadata_end(); I != E; ++I) { 840 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName()); 841 // Add Src elements into Dest node. 842 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) 843 DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap, 844 RF_None, &TypeMap)); 845 } 846} 847 848bool ModuleLinker::run() { 849 assert(DstM && "Null Destination module"); 850 assert(SrcM && "Null Source Module"); 851 852 // Inherit the target data from the source module if the destination module 853 // doesn't have one already. 854 if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty()) 855 DstM->setDataLayout(SrcM->getDataLayout()); 856 857 // Copy the target triple from the source to dest if the dest's is empty. 858 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty()) 859 DstM->setTargetTriple(SrcM->getTargetTriple()); 860 861 if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() && 862 SrcM->getDataLayout() != DstM->getDataLayout()) 863 errs() << "WARNING: Linking two modules of different data layouts!\n"; 864 if (!SrcM->getTargetTriple().empty() && 865 DstM->getTargetTriple() != SrcM->getTargetTriple()) { 866 errs() << "WARNING: Linking two modules of different target triples: "; 867 if (!SrcM->getModuleIdentifier().empty()) 868 errs() << SrcM->getModuleIdentifier() << ": "; 869 errs() << "'" << SrcM->getTargetTriple() << "' and '" 870 << DstM->getTargetTriple() << "'\n"; 871 } 872 873 // Append the module inline asm string. 874 if (!SrcM->getModuleInlineAsm().empty()) { 875 if (DstM->getModuleInlineAsm().empty()) 876 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm()); 877 else 878 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+ 879 SrcM->getModuleInlineAsm()); 880 } 881 882 // Update the destination module's dependent libraries list with the libraries 883 // from the source module. There's no opportunity for duplicates here as the 884 // Module ensures that duplicate insertions are discarded. 885 for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end(); 886 SI != SE; ++SI) 887 DstM->addLibrary(*SI); 888 889 // If the source library's module id is in the dependent library list of the 890 // destination library, remove it since that module is now linked in. 891 StringRef ModuleId = SrcM->getModuleIdentifier(); 892 if (!ModuleId.empty()) 893 DstM->removeLibrary(sys::path::stem(ModuleId)); 894 895 896 // Loop over all of the linked values to compute type mappings. 897 computeTypeMapping(); 898 899 // Insert all of the globals in src into the DstM module... without linking 900 // initializers (which could refer to functions not yet mapped over). 901 for (Module::global_iterator I = SrcM->global_begin(), 902 E = SrcM->global_end(); I != E; ++I) 903 if (linkGlobalProto(I)) 904 return true; 905 906 // Link the functions together between the two modules, without doing function 907 // bodies... this just adds external function prototypes to the DstM 908 // function... We do this so that when we begin processing function bodies, 909 // all of the global values that may be referenced are available in our 910 // ValueMap. 911 for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) 912 if (linkFunctionProto(I)) 913 return true; 914 915 // If there were any aliases, link them now. 916 for (Module::alias_iterator I = SrcM->alias_begin(), 917 E = SrcM->alias_end(); I != E; ++I) 918 if (linkAliasProto(I)) 919 return true; 920 921 for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i) 922 linkAppendingVarInit(AppendingVars[i]); 923 924 // Update the initializers in the DstM module now that all globals that may 925 // be referenced are in DstM. 926 linkGlobalInits(); 927 928 // Link in the function bodies that are defined in the source module into 929 // DstM. 930 for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) { 931 if (SF->isDeclaration()) continue; // No body if function is external. 932 933 linkFunctionBody(cast<Function>(ValueMap[SF]), SF); 934 } 935 936 // Resolve all uses of aliases with aliasees. 937 linkAliasBodies(); 938 939 // Remap all of the named mdnoes in Src into the DstM module. We do this 940 // after linking GlobalValues so that MDNodes that reference GlobalValues 941 // are properly remapped. 942 linkNamedMDNodes(); 943 944 // Now that all of the types from the source are used, resolve any structs 945 // copied over to the dest that didn't exist there. 946 TypeMap.linkDefinedTypeBodies(); 947 948 return false; 949} 950 951//===----------------------------------------------------------------------===// 952// LinkModules entrypoint. 953//===----------------------------------------------------------------------===// 954 955// LinkModules - This function links two modules together, with the resulting 956// left module modified to be the composite of the two input modules. If an 957// error occurs, true is returned and ErrorMsg (if not null) is set to indicate 958// the problem. Upon failure, the Dest module could be in a modified state, and 959// shouldn't be relied on to be consistent. 960bool Linker::LinkModules(Module *Dest, Module *Src, std::string *ErrorMsg) { 961 ModuleLinker TheLinker(Dest, Src); 962 if (TheLinker.run()) { 963 if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg; 964 return true; 965 } 966 967 return false; 968} 969