Remove special casing of global_ctors in GDA.

This is no longer necessary, as placing these in the start function during CallConstructors ensures they are reachable, and thus GDA will not remove them.

Author: Maqrkk

llvm/include/llvm/Cheerp/Utility.h

@@ -308,6 +308,7 @@ struct GlobalConstructor
 };
 
 std::vector<llvm::Constant*> getGlobalConstructors(llvm::Module& M);
+void removeGlobalConstructorsGlobal(llvm::Module& M);
 
 uint32_t getIntFromValue(const llvm::Value* v);
 

llvm/lib/CheerpUtils/CallConstructors.cpp

@@ -63,9 +63,8 @@ PreservedAnalyses CallConstructorsPass::run(llvm::Module &M, llvm::ModuleAnalysi
 		Builder.CreateCall(GetEnviron->getFunctionType(), GetEnviron);
 
 	for (Constant* C: cheerp::getGlobalConstructors(M))
-	{
 		Builder.CreateCall(Ty, cast<Function>(C->getAggregateElement(1)->stripPointerCastsSafe()));
-	}
+	removeGlobalConstructorsGlobal(M);
 
 	if (useUtilityThread)
 	{

llvm/lib/CheerpUtils/GlobalDepsAnalyzer.cpp

@@ -1582,7 +1582,7 @@ int GlobalDepsAnalyzer::filterModule( const DenseSet<const Function*>& droppedMa
 			bool isClient = TypeSupport::isClientGlobal(var);
 			if( var->hasInitializer() )
 			{
-				if( !WasmSharedModule && !isClient && var->getName()!="llvm.global_ctors" )
+				if( !WasmSharedModule && !isClient)
 					var->setLinkage(GlobalValue::InternalLinkage);
 			}
 			else if( !isClient  && var->getName() != "__cxa_cheerp_clause_table")

llvm/lib/CheerpUtils/Utility.cpp

@@ -1038,6 +1038,14 @@ std::vector<Constant*> getGlobalConstructors(Module& module)
 	return ret;
 }
 
+void removeGlobalConstructorsGlobal(Module& M)
+{
+	GlobalVariable* var = M.getGlobalVariable("llvm.global_ctors");
+	if (!var)
+		return;
+	var->eraseFromParent();
+}
+
 const llvm::Loop* findCommonLoop(const llvm::LoopInfo* LI, const llvm::BasicBlock* first, const llvm::BasicBlock* second)
 {
 	//Find the innermost common loop between two BB.

llvm/lib/CheerpWriter/CheerpWriter.cpp

@@ -6719,9 +6719,6 @@ void CheerpWriter::compileGenericJS()
 	}
 	for ( const GlobalVariable & GV : module.getGlobalList() )
 	{
-		// Skip global ctors array
-		if (GV.getName() == "llvm.global_ctors")
-			continue;
 		if (GV.getSection() != StringRef("asmjs"))
 			compileGlobal(GV);
 	}