Merge from mainline. (b69f6c02) · Commits · llvm-doe / llvm-project

llvm/lib/Linker/LinkModules.cpp

+39 −25

Original line number	Diff line number	Diff line
		@@ -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())
		// 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 dest if global variable, check that initializers match.
		if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV)) {
		if (DGVar->hasInitializer()) {
		if (SGV->hasExternalLinkage()) {
		if (DGV->getInitializer() != SInit)
		return Error(Err, "Global Variable Collision on '" + SGV->getName() +
		if (DGVar->getInitializer() != SInit)
		return Error(Err, "Global Variable Collision on '" +
		SGV->getName() +
		"': global variables have different initializers");
		} else if (DGV->mayBeOverridden()) {
		} 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 (DGV->hasAppendingLinkage()) {
		} else if (DGVar->hasAppendingLinkage()) {
		assert(0 && "Appending linkage unimplemented!");
		} else {
		assert(0 && "Unknown linkage!");
		}
		} else {
		// Copy the initializer over now...
		DGV->setInitializer(SInit);
		DGVar->setInitializer(SInit);
		}
		} else {
		// 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());
		}
		}
		}