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Properly link globals with aliases 

llvm-svn: 48179
This commit is contained in:
Anton Korobeynikov 2008-03-10 22:34:28 +00:00
parent 1d9848e391
commit e79f4c77f0
1 changed files with 41 additions and 20 deletions
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61
llvm/lib/Linker/LinkModules.cpp
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@ -462,8 +462,9 @@ static bool LinkGlobals(Module *Dest, const Module *Src,
for (Module::const_global_iterator I = Src->global_begin(), E = Src->global_end();
I != E; ++I) {
const GlobalVariable *SGV = I;
GlobalVariable *DGV = 0;
// Check to see if may have to link the global.
GlobalValue *DGV = 0;
// Check to see if may have to link the global with the global
if (SGV->hasName() && !SGV->hasInternalLinkage()) {
DGV = Dest->getGlobalVariable(SGV->getName());
if (DGV && DGV->getType() != SGV->getType())
@ -472,6 +473,15 @@ static bool LinkGlobals(Module *Dest, const Module *Src,
&Dest->getTypeSymbolTable(), "");
}
// Check to see if may have to link the global with the alias
if (SGV->hasName() && !SGV->hasInternalLinkage()) {
DGV = Dest->getNamedAlias(SGV->getName());
if (DGV && DGV->getType() != SGV->getType())
// If types don't agree due to opaque types, try to resolve them.
RecursiveResolveTypes(SGV->getType(), DGV->getType(),
&Dest->getTypeSymbolTable(), "");
}
if (DGV && DGV->hasInternalLinkage())
DGV = 0;
@ -526,26 +536,37 @@ static bool LinkGlobals(Module *Dest, const Module *Src,
// Keep track that this is an appending variable...
AppendingVars.insert(std::make_pair(SGV->getName(), NewDGV));
} else {
} else if (GlobalAlias *DGA = dyn_cast<GlobalAlias>(DGV)) {
// SGV is global, but DGV is alias. The only valid mapping is when SGV is
// external declaration, which is effectively a no-op. Also make sure
// linkage is correct.
if (SGV->isDeclaration() && !LinkFromSrc) {
// Make sure to remember this mapping...
ValueMap.insert(std::make_pair(SGV, DGA));
} else
return Error(Err, "Global-Alias Collision on '" +
ToStr(SGV->getType(), Src) +"':%"+SGV->getName()+
" - symbol multiple defined");
} else if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
// Otherwise, perform the mapping as instructed by GetLinkageResult.
if (LinkFromSrc) {
// Propagate alignment, section, and visibility info.
CopyGVAttributes(DGV, SGV);
CopyGVAttributes(DGVar, SGV);
// 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()) {
if (SGV->getType() != DGVar->getType()) {
GlobalVariable *NewDGV =
new GlobalVariable(SGV->getType()->getElementType(),
DGV->isConstant(), DGV->getLinkage(),
/*init*/0, DGV->getName(), Dest);
CopyGVAttributes(NewDGV, DGV);
DGVar->isConstant(), DGVar->getLinkage(),
/*init*/0, DGVar->getName(), Dest);
CopyGVAttributes(NewDGV, DGVar);
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV,
DGV->getType()));
// DGV will conflict with NewDGV because they both had the same
DGVar->getType()));
// DGVar will conflict with NewDGV because they both had the same
// name. We must erase this now so ForceRenaming doesn't assert
// because DGV might not have internal linkage.
DGV->eraseFromParent();
DGVar->eraseFromParent();
// If the symbol table renamed the global, but it is an externally
// visible symbol, DGV must be an existing global with internal
@ -554,26 +575,26 @@ static bool LinkGlobals(Module *Dest, const Module *Src,
!NewDGV->hasInternalLinkage())
ForceRenaming(NewDGV, SGV->getName());
DGV = NewDGV;
DGVar = NewDGV;
}
// Inherit const as appropriate
DGV->setConstant(SGV->isConstant());
DGVar->setConstant(SGV->isConstant());
// Set initializer to zero, so we can link the stuff later
DGV->setInitializer(0);
DGVar->setInitializer(0);
} else {
// Special case for const propagation
if (DGV->isDeclaration() && SGV->isConstant() && !DGV->isConstant())
DGV->setConstant(true);
if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
DGVar->setConstant(true);
}
// Set calculated linkage
DGV->setLinkage(NewLinkage);
DGVar->setLinkage(NewLinkage);
// Make sure to remember this mapping...
ValueMap.insert(std::make_pair(SGV,
ConstantExpr::getBitCast(DGV,
ConstantExpr::getBitCast(DGVar,
SGV->getType())));
}
}
@ -659,7 +680,7 @@ static bool LinkAlias(Module *Dest, const Module *Src,
// Proceed to 'common' steps
} else
return Error(Err, "Alias Collision on '" +
return Error(Err, "Global-Alias Collision on '" +
ToStr(SGA->getType(), Src) +"':%"+SGA->getName()+
" - symbol multiple defined");
} else if (Function *DF = Dest->getFunction(SGA->getName())) {
@ -686,7 +707,7 @@ static bool LinkAlias(Module *Dest, const Module *Src,
// Proceed to 'common' steps
} else
return Error(Err, "Alias Collision on '" +
return Error(Err, "Function-Alias Collision on '" +
ToStr(SGA->getType(), Src) +"':%"+SGA->getName()+
" - symbol multiple defined");
} else {