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llvm/lib/Linker/LinkModules.cpp

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//===- Linker.cpp - Module Linker Implementation --------------------------===//
//
// 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/Transforms/Utils/Linker.h"
#include "llvm/Module.h"
#include "llvm/SymbolTable.h"
#include "llvm/DerivedTypes.h"
#include "llvm/iOther.h"
#include "llvm/Constants.h"
// 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;
}
// ResolveTypes - Attempt to link the two specified types together. Return true
// if there is an error and they cannot yet be linked.
//
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
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 RecursiveResolveTypes(const PATypeHolder &DestTy,
const PATypeHolder &SrcTy,
SymbolTable *DestST, const std::string &Name){
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->getPrimitiveID() != SrcTyT->getPrimitiveID()) return true;
// Otherwise, resolve the used type used by this derived type...
switch (DestTyT->getPrimitiveID()) {
case Type::FunctionTyID: {
if (cast<FunctionType>(DestTyT)->isVarArg() !=
cast<FunctionType>(SrcTyT)->isVarArg())
return true;
for (unsigned i = 0, e = getFT(DestTy)->getNumContainedTypes(); i != e; ++i)
if (RecursiveResolveTypes(getFT(DestTy)->getContainedType(i),
getFT(SrcTy)->getContainedType(i), DestST,Name))
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 (RecursiveResolveTypes(getST(DestTy)->getContainedType(i),
getST(SrcTy)->getContainedType(i), DestST,Name))
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 RecursiveResolveTypes(DAT->getElementType(), SAT->getElementType(),
DestST, Name);
}
case Type::PointerTyID:
return RecursiveResolveTypes(
cast<PointerType>(DestTy.get())->getElementType(),
cast<PointerType>(SrcTy.get())->getElementType(),
DestST, Name);
default: assert(0 && "Unexpected type!"); return true;
}
}
// 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::const_iterator PI = SrcST->find(Type::TypeTy);
if (PI == SrcST->end()) return false; // No named types, do nothing.
// Some types cannot be resolved immediately becuse 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;
const SymbolTable::VarMap &VM = PI->second;
for (SymbolTable::type_const_iterator I = VM.begin(), E = VM.end();
I != E; ++I) {
const std::string &Name = I->first;
Type *RHS = cast<Type>(I->second);
// Check to see if this type name is already in the dest module...
Type *Entry = cast_or_null<Type>(DestST->lookup(Type::TypeTy, 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 = cast<Type>(VM.find(Name)->second);
Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, 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(cast<Type>(VM.find(Name)->second));
PATypeHolder T2(cast<Type>(DestST->lookup(Type::TypeTy, 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.
// Report the error.
if (DelayedTypesToResolve.size() == OldSize) {
// Build up an error message of all of the mismatched types.
std::string ErrorMessage;
for (unsigned i = 0, e = DelayedTypesToResolve.size(); i != e; ++i) {
const std::string &Name = DelayedTypesToResolve[i];
const Type *T1 = cast<Type>(VM.find(Name)->second);
const Type *T2 = cast<Type>(DestST->lookup(Type::TypeTy, Name));
ErrorMessage += " Type named '" + Name +
"' conflicts.\n Src='" + T1->getDescription() +
"'.\n Dest='" + T2->getDescription() + "'\n";
}
return Error(Err, "Type conflict between types in modules:\n" +
ErrorMessage);
}
}
}
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 LocalMap and GlobalMap 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*> &LocalMap,
std::map<const Value*, Value*> *GlobalMap) {
std::map<const Value*,Value*>::const_iterator I = LocalMap.find(In);
if (I != LocalMap.end()) return I->second;
if (GlobalMap) {
I = GlobalMap->find(In);
if (I != GlobalMap->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))
return const_cast<Constant*>(CPV); // Simple constants stay identical...
Constant *Result = 0;
if (const ConstantArray *CPA = dyn_cast<ConstantArray>(CPV)) {
const std::vector<Use> &Ops = CPA->getValues();
std::vector<Constant*> Operands(Ops.size());
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
Operands[i] =
cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
Result = ConstantArray::get(cast<ArrayType>(CPA->getType()), Operands);
} else if (const ConstantStruct *CPS = dyn_cast<ConstantStruct>(CPV)) {
const std::vector<Use> &Ops = CPS->getValues();
std::vector<Constant*> Operands(Ops.size());
for (unsigned i = 0; i < Ops.size(); ++i)
Operands[i] =
cast<Constant>(RemapOperand(Ops[i], LocalMap, GlobalMap));
Result = ConstantStruct::get(cast<StructType>(CPS->getType()), Operands);
} else if (isa<ConstantPointerNull>(CPV)) {
Result = const_cast<Constant*>(CPV);
} else if (const ConstantPointerRef *CPR =
dyn_cast<ConstantPointerRef>(CPV)) {
Value *V = RemapOperand(CPR->getValue(), LocalMap, GlobalMap);
Result = ConstantPointerRef::get(cast<GlobalValue>(V));
} else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CPV)) {
if (CE->getOpcode() == Instruction::GetElementPtr) {
Value *Ptr = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
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),
LocalMap, GlobalMap)));
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), LocalMap, GlobalMap);
Result = ConstantExpr::getCast(cast<Constant>(V), CE->getType());
} else if (CE->getNumOperands() == 2) {
// Binary operator...
Value *V1 = RemapOperand(CE->getOperand(0), LocalMap, GlobalMap);
Value *V2 = RemapOperand(CE->getOperand(1), LocalMap, GlobalMap);
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...
if (GlobalMap)
GlobalMap->insert(std::make_pair(In, Result));
else
LocalMap.insert(std::make_pair(In, Result));
return Result;
}
std::cerr << "XXX LocalMap: \n";
PrintMap(LocalMap);
if (GlobalMap) {
std::cerr << "XXX GlobalMap: \n";
PrintMap(*GlobalMap);
}
std::cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
assert(0 && "Couldn't remap value!");
return 0;
}
// LinkGlobals - Loop through the global variables in the src module and merge
// them into the dest module.
//
static bool LinkGlobals(Module *Dest, const Module *Src,
std::map<const Value*, Value*> &ValueMap,
std::multimap<std::string, GlobalVariable *> &AppendingVars,
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::const_giterator I = Src->gbegin(), E = Src->gend(); I != E; ++I){
const GlobalVariable *SGV = I;
GlobalVariable *DGV = 0;
if (SGV->hasName()) {
// A same named thing is a global variable, because the only two things
// that may be in a module level symbol table are Global Vars and
// Functions, and they both have distinct, nonoverlapping, possible types.
//
DGV = cast_or_null<GlobalVariable>(ST->lookup(SGV->getType(),
SGV->getName()));
}
assert(SGV->hasInitializer() || SGV->hasExternalLinkage() &&
"Global must either be external or have an initializer!");
bool SGExtern = SGV->isExternal();
bool DGExtern = DGV ? DGV->isExternal() : false;
if (!DGV || DGV->hasInternalLinkage() || SGV->hasInternalLinkage()) {
// 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()){
assert(DGV && DGV->getName() == SGV->getName() &&
DGV->hasInternalLinkage());
DGV->setName("");
NewDGV->setName(SGV->getName()); // Force the name back
DGV->setName(SGV->getName()); // This will cause a renaming
assert(NewDGV->getName() == SGV->getName() &&
DGV->getName() != 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 (SGV->isExternal()) {
// If SGV is external or if both SGV & DGV are external.. Just link the
// external globals, we aren't adding anything.
ValueMap.insert(std::make_pair(SGV, DGV));
} else if (DGV->isExternal()) { // If DGV is external but SGV is not...
ValueMap.insert(std::make_pair(SGV, DGV));
DGV->setLinkage(SGV->getLinkage()); // Inherit linkage!
} else if (SGV->getLinkage() != DGV->getLinkage()) {
return Error(Err, "Global variables named '" + SGV->getName() +
"' have different linkage specifiers!");
} else if (SGV->hasExternalLinkage()) {
// Allow linking two exactly identical external global variables...
if (SGV->isConstant() != DGV->isConstant() ||
SGV->getInitializer() != DGV->getInitializer())
return Error(Err, "Global Variable Collision on '" +
SGV->getType()->getDescription() + " %" + SGV->getName() +
"' - Global variables differ in const'ness");
ValueMap.insert(std::make_pair(SGV, DGV));
} else if (SGV->hasLinkOnceLinkage()) {
// If the global variable has a name, and that name is already in use in
// the Dest module, make sure that the name is a compatible global
// variable...
//
// Check to see if the two GV's have the same Const'ness...
if (SGV->isConstant() != DGV->isConstant())
return Error(Err, "Global Variable Collision on '" +
SGV->getType()->getDescription() + " %" + SGV->getName() +
"' - Global variables differ in const'ness");
// Okay, everything is cool, remember the mapping...
ValueMap.insert(std::make_pair(SGV, DGV));
} else if (SGV->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 {
assert(0 && "Unknown linkage!");
}
}
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_giterator I = Src->gbegin(), E = Src->gend(); 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, 0));
GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[SGV]);
if (DGV->hasInitializer()) {
assert(SGV->getLinkage() == DGV->getLinkage());
if (SGV->hasExternalLinkage()) {
if (DGV->getInitializer() != SInit)
return Error(Err, "Global Variable Collision on '" +
SGV->getType()->getDescription() +"':%"+SGV->getName()+
" - Global variables have different initializers");
} else if (DGV->hasLinkOnceLinkage()) {
// 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::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())
// The same named thing is a Function, because the only two things
// that may be in a module level symbol table are Global Vars and
// Functions, and they both have distinct, nonoverlapping, possible types.
//
DF = cast_or_null<Function>(ST->lookup(SF->getType(), SF->getName()));
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);
// 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()) {
assert(DF && DF->getName() == SF->getName() &&DF->hasInternalLinkage());
DF->setName("");
NewDF->setName(SF->getName()); // Force the name back
DF->setName(SF->getName()); // This will cause a renaming
assert(NewDF->getName() == SF->getName() &&
DF->getName() != 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->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 '" +
SF->getFunctionType()->getDescription() + "':\"" +
SF->getName() + "\" - Function is already defined!");
} else if (SF->hasLinkOnceLinkage()) {
// Completely ignore the source function.
ValueMap.insert(std::make_pair(SF, DF));
} 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, const Function *Src,
std::map<const Value*, Value*> &GlobalMap,
std::string *Err) {
assert(Src && Dest && Dest->isExternal() && !Src->isExternal());
std::map<const Value*, Value*> LocalMap; // Map for function local values
// Go through and convert function arguments over...
Function::aiterator DI = Dest->abegin();
for (Function::const_aiterator I = Src->abegin(), E = Src->aend();
I != E; ++I, ++DI) {
DI->setName(I->getName()); // Copy the name information over...
// Add a mapping to our local map
LocalMap.insert(std::make_pair(I, DI));
}
// Loop over all of the basic blocks, copying the instructions over...
//
for (Function::const_iterator I = Src->begin(), E = Src->end(); I != E; ++I) {
// Create new basic block and add to mapping and the Dest function...
BasicBlock *DBB = new BasicBlock(I->getName(), Dest);
LocalMap.insert(std::make_pair(I, DBB));
// Loop over all of the instructions in the src basic block, copying them
// over. Note that this is broken in a strict sense because the cloned
// instructions will still be referencing values in the Src module, not
// the remapped values. In our case, however, we will not get caught and
// so we can delay patching the values up until later...
//
for (BasicBlock::const_iterator II = I->begin(), IE = I->end();
II != IE; ++II) {
Instruction *DI = II->clone();
DI->setName(II->getName());
DBB->getInstList().push_back(DI);
LocalMap.insert(std::make_pair(II, DI));
}
}
// 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)
*OI = RemapOperand(*OI, LocalMap, &GlobalMap);
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, const 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::const_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()) {
if (DF->hasLinkOnceLinkage()) continue; // No relinkage for link-once!
if (Err)
*Err = "Function '" + (SF->hasName() ? SF->getName() :std::string(""))
+ "' body multiply defined!";
return true;
}
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);
ConstantArray *I = cast<ConstantArray>(G1->getInitializer());
for (unsigned i = 0, e = T1->getNumElements(); i != e; ++i)
Inits.push_back(cast<Constant>(I->getValues()[i]));
I = cast<ConstantArray>(G2->getInitializer());
for (unsigned i = 0, e = T2->getNumElements(); i != e; ++i)
Inits.push_back(cast<Constant>(I->getValues()[i]));
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!
ConstantPointerRef *NGCP = ConstantPointerRef::get(NG);
G1->replaceAllUsesWith(ConstantExpr::getCast(NGCP, G1->getType()));
G2->replaceAllUsesWith(ConstantExpr::getCast(NGCP, 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 LinkModules(Module *Dest, const Module *Src, std::string *ErrorMsg) {
if (Dest->getEndianness() != Src->getEndianness())
std::cerr << "WARNING: Linking two modules of different endianness!\n";
if (Dest->getPointerSize() != Src->getPointerSize())
std::cerr << "WARNING: Linking two modules of different pointer size!\n";
// 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;
// Add all of the appending globals already in the Dest module to
// AppendingVars.
for (Module::giterator I = Dest->gbegin(), E = Dest->gend(); I != E; ++I)
if (I->hasAppendingLinkage())
AppendingVars.insert(std::make_pair(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, 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, 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;
return false;
}
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