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Also properly handle linking of strong alias and weak global

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57595 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov 2008-10-15 20:10:50 +00:00
parent e655e37032
commit d13726f1e9
1 changed files with 38 additions and 24 deletions
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62
lib/Linker/LinkModules.cpp
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@ -662,12 +662,15 @@ static bool LinkGlobals(Module *Dest, const Module *Src,
if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
DGVar->setConstant(true);
// 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 calculation was correct.
if (isa<GlobalAlias>(DGV) && !SGV->isDeclaration())
return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
"': symbol multiple defined");
// SGV is global, but DGV is alias.
if (isa<GlobalAlias>(DGV)) {
// The only valid mappings are:
// - SGV is external declaration, which is effectively a no-op.
// - SGV is weak, when we just need to throw SGV out.
if (!SGV->isDeclaration() && !SGV->mayBeOverridden())
return Error(Err, "Global-Alias Collision on '" + SGV->getName() +
"': symbol multiple defined");
}
// Set calculated linkage
DGV->setLinkage(NewLinkage);
@ -854,28 +857,39 @@ static bool LinkGlobalInits(Module *Dest, const Module *Src,
// Figure out what the initializer looks like in the dest module...
Constant *SInit =
cast<Constant>(RemapOperand(SGV->getInitializer(), ValueMap));
// Grab destination global variable or alias.
GlobalValue *DGV = cast<GlobalValue>(ValueMap[SGV]->stripPointerCasts());
GlobalVariable *DGV =
cast<GlobalVariable>(ValueMap[SGV]->stripPointerCasts());
if (DGV->hasInitializer()) {
if (SGV->hasExternalLinkage()) {
if (DGV->getInitializer() != SInit)
return Error(Err, "Global Variable Collision on '" + SGV->getName() +
"': global variables have different initializers");
} else if (DGV->mayBeOverridden()) {
// Nothing is required, mapped values will take the new global
// automatically.
} else if (SGV->mayBeOverridden()) {
// Nothing is required, mapped values will take the new global
// automatically.
} else if (DGV->hasAppendingLinkage()) {
assert(0 && "Appending linkage unimplemented!");
// If dest if global variable, check that initializers match.
if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
if (DGVar->hasInitializer()) {
if (SGV->hasExternalLinkage()) {
if (DGVar->getInitializer() != SInit)
return Error(Err, "Global Variable Collision on '" +
SGV->getName() +
"': global variables have different initializers");
} else if (DGVar->mayBeOverridden()) {
// Nothing is required, mapped values will take the new global
// automatically.
} else if (SGV->mayBeOverridden()) {
// Nothing is required, mapped values will take the new global
// automatically.
} else if (DGVar->hasAppendingLinkage()) {
assert(0 && "Appending linkage unimplemented!");
} else {
assert(0 && "Unknown linkage!");
}
} else {
assert(0 && "Unknown linkage!");
// Copy the initializer over now...
DGVar->setInitializer(SInit);
}
} else {
// Copy the initializer over now...
DGV->setInitializer(SInit);
// Destination is alias, the only valid situation is when source is
// weak. Also, note, that we already checked linkage in LinkGlobals(),
// thus we assert here.
// FIXME: Should we weaken this assumption, 'dereference' alias and
// check for initializer of aliasee?
assert(SGV->mayBeOverridden());
}
}
}