view gen/functions.cpp @ 117:56a21f3e5d3e trunk

[svn r121] Finished ModuleInfo implementation. Static ctors/dtors now work according to spec. Changed class vtable types slightly in some cases. Overridden functions now always take the the type of the first class declaring the method as this parameter. This helps when using headers (w. implementation somewhere else)
author lindquist
date Mon, 26 Nov 2007 04:49:23 +0100
parents fd7ad91fd713
children 79c9ac745fbc
line wrap: on
line source

#include "gen/llvm.h"

#include "mtype.h"
#include "aggregate.h"
#include "init.h"
#include "declaration.h"
#include "template.h"
#include "module.h"
#include "statement.h"

#include "gen/irstate.h"
#include "gen/tollvm.h"
#include "gen/runtime.h"
#include "gen/arrays.h"
#include "gen/logger.h"
#include "gen/functions.h"
#include "gen/todebug.h"
#include "gen/classes.h"

const llvm::FunctionType* DtoFunctionType(Type* type, const llvm::Type* thistype, bool ismain)
{
    TypeFunction* f = (TypeFunction*)type;
    assert(f != 0);

    if (type->llvmType != NULL) {
        return llvm::cast<llvm::FunctionType>(type->llvmType->get());
    }

    bool typesafeVararg = false;
    if (f->linkage == LINKd && f->varargs == 1) {
        typesafeVararg = true;
    }

    // return value type
    const llvm::Type* rettype;
    const llvm::Type* actualRettype;
    Type* rt = f->next;
    bool retinptr = false;
    bool usesthis = false;

    if (ismain) {
        rettype = llvm::Type::Int32Ty;
        actualRettype = rettype;
    }
    else {
        assert(rt);
        Type* rtfin = DtoDType(rt);
        if (DtoIsPassedByRef(rt)) {
            rettype = llvm::PointerType::get(DtoType(rt));
            actualRettype = llvm::Type::VoidTy;
            f->llvmRetInPtr = retinptr = true;
        }
        else {
            rettype = DtoType(rt);
            actualRettype = rettype;
        }
    }

    // parameter types
    std::vector<const llvm::Type*> paramvec;

    if (retinptr) {
        Logger::cout() << "returning through pointer parameter: " << *rettype << '\n';
        paramvec.push_back(rettype);
    }

    if (thistype) {
        paramvec.push_back(thistype);
        usesthis = true;
    }

    if (typesafeVararg) {
        ClassDeclaration* ti = Type::typeinfo;
        ti->toObjFile();
        DtoForceConstInitDsymbol(ti);
        assert(ti->llvmInitZ);
        std::vector<const llvm::Type*> types;
        types.push_back(DtoSize_t());
        types.push_back(llvm::PointerType::get(llvm::PointerType::get(ti->llvmInitZ->getType())));
        const llvm::Type* t1 = llvm::StructType::get(types);
        paramvec.push_back(llvm::PointerType::get(t1));
        paramvec.push_back(llvm::PointerType::get(llvm::Type::Int8Ty));
    }

    size_t n = Argument::dim(f->parameters);

    for (int i=0; i < n; ++i) {
        Argument* arg = Argument::getNth(f->parameters, i);
        // ensure scalar
        Type* argT = DtoDType(arg->type);
        assert(argT);

        if ((arg->storageClass & STCref) || (arg->storageClass & STCout)) {
            //assert(arg->vardecl);
            //arg->vardecl->refparam = true;
        }
        else
            arg->llvmCopy = true;

        const llvm::Type* at = DtoType(argT);
        if (isaStruct(at)) {
            Logger::println("struct param");
            paramvec.push_back(llvm::PointerType::get(at));
        }
        else if (isaArray(at)) {
            Logger::println("sarray param");
            assert(argT->ty == Tsarray);
            //paramvec.push_back(llvm::PointerType::get(at->getContainedType(0)));
            paramvec.push_back(llvm::PointerType::get(at));
        }
        else if (llvm::isa<llvm::OpaqueType>(at)) {
            Logger::println("opaque param");
            assert(argT->ty == Tstruct || argT->ty == Tclass);
            paramvec.push_back(llvm::PointerType::get(at));
        }
        else {
            if (!arg->llvmCopy) {
                Logger::println("ref param");
                at = llvm::PointerType::get(at);
            }
            else {
                Logger::println("in param");
            }
            paramvec.push_back(at);
        }
    }

    // construct function type
    bool isvararg = !typesafeVararg && f->varargs;
    llvm::FunctionType* functype = llvm::FunctionType::get(actualRettype, paramvec, isvararg);

    f->llvmRetInPtr = retinptr;
    f->llvmUsesThis = usesthis;

    //if (!f->llvmType)
        f->llvmType = new llvm::PATypeHolder(functype);
    //else
        //assert(functype == f->llvmType->get());

    return functype;
}

//////////////////////////////////////////////////////////////////////////////////////////

static const llvm::FunctionType* DtoVaFunctionType(FuncDeclaration* fdecl)
{
    // type has already been resolved
    if (fdecl->type->llvmType != 0) {
        return llvm::cast<llvm::FunctionType>(fdecl->type->llvmType->get());
    }

    TypeFunction* f = (TypeFunction*)fdecl->type;
    assert(f != 0);

    const llvm::PointerType* i8pty = llvm::PointerType::get(llvm::Type::Int8Ty);
    std::vector<const llvm::Type*> args;

    if (fdecl->llvmInternal == LLVMva_start) {
        args.push_back(i8pty);
    }
    else if (fdecl->llvmInternal == LLVMva_intrinsic) {
        size_t n = Argument::dim(f->parameters);
        for (size_t i=0; i<n; ++i) {
            args.push_back(i8pty);
        }
    }
    else
    assert(0);

    const llvm::FunctionType* fty = llvm::FunctionType::get(llvm::Type::VoidTy, args, false);

    f->llvmType = new llvm::PATypeHolder(fty);

    return fty;
}

//////////////////////////////////////////////////////////////////////////////////////////

const llvm::FunctionType* DtoFunctionType(FuncDeclaration* fdecl)
{
    if ((fdecl->llvmInternal == LLVMva_start) || (fdecl->llvmInternal == LLVMva_intrinsic)) {
        return DtoVaFunctionType(fdecl);
    }

    // type has already been resolved
    if (fdecl->type->llvmType != 0) {
        return llvm::cast<llvm::FunctionType>(fdecl->type->llvmType->get());
    }

    const llvm::Type* thisty = NULL;
    if (fdecl->needThis()) {
        if (AggregateDeclaration* ad = fdecl->isMember()) {
            Logger::print("isMember = this is: %s\n", ad->type->toChars());
            thisty = DtoType(ad->type);
            //Logger::cout() << "this llvm type: " << *thisty << '\n';
            if (isaStruct(thisty) || (!gIR->structs.empty() && thisty == gIR->topstruct()->recty.get()))
                thisty = llvm::PointerType::get(thisty);
        }
        else
        assert(0);
    }
    else if (fdecl->isNested()) {
        thisty = llvm::PointerType::get(llvm::Type::Int8Ty);
    }

    const llvm::FunctionType* functype = DtoFunctionType(fdecl->type, thisty, fdecl->isMain());

    return functype;
}

//////////////////////////////////////////////////////////////////////////////////////////

static llvm::Function* DtoDeclareVaFunction(FuncDeclaration* fdecl)
{
    TypeFunction* f = (TypeFunction*)DtoDType(fdecl->type);
    const llvm::FunctionType* fty = DtoVaFunctionType(fdecl);
    llvm::Constant* fn = 0;

    if (fdecl->llvmInternal == LLVMva_start) {
        fn = gIR->module->getOrInsertFunction("llvm.va_start", fty);
        assert(fn);
    }
    else if (fdecl->llvmInternal == LLVMva_intrinsic) {
        fn = gIR->module->getOrInsertFunction(fdecl->llvmInternal1, fty);
        assert(fn);
    }
    else
    assert(0);

    llvm::Function* func = llvm::dyn_cast<llvm::Function>(fn);
    assert(func);
    assert(func->isIntrinsic());
    fdecl->llvmValue = func;
    return func;
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoResolveFunction(FuncDeclaration* fdecl)
{
    if (fdecl->llvmResolved) return;
    fdecl->llvmResolved = true;

    Logger::println("DtoResolveFunction(%s)", fdecl->toPrettyChars());
    LOG_SCOPE;

    if (fdecl->llvmRunTimeHack) {
        gIR->declareList.push_back(fdecl);
        return;
    }

    if (fdecl->isUnitTestDeclaration()) {
        Logger::attention("ignoring unittest declaration: %s", fdecl->toChars());
        return;
    }

    if (fdecl->parent)
    if (TemplateInstance* tinst = fdecl->parent->isTemplateInstance())
    {
        TemplateDeclaration* tempdecl = tinst->tempdecl;
        if (tempdecl->llvmInternal == LLVMva_arg)
        {
            Logger::println("magic va_arg found");
            fdecl->llvmInternal = LLVMva_arg;
            fdecl->llvmDeclared = true;
            fdecl->llvmInitialized = true;
            fdecl->llvmDefined = true;
            return; // this gets mapped to an instruction so a declaration makes no sence
        }
        else if (tempdecl->llvmInternal == LLVMva_start)
        {
            Logger::println("magic va_start found");
            fdecl->llvmInternal = LLVMva_start;
        }
    }

    DtoFunctionType(fdecl);

    // queue declaration
    if (!fdecl->isAbstract())
        gIR->declareList.push_back(fdecl);
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoDeclareFunction(FuncDeclaration* fdecl)
{
    if (fdecl->llvmDeclared) return;
    fdecl->llvmDeclared = true;

    Logger::println("DtoDeclareFunction(%s)", fdecl->toPrettyChars());
    LOG_SCOPE;

    assert(!fdecl->isAbstract());

    if (fdecl->llvmRunTimeHack) {
        Logger::println("runtime hack func chars: %s", fdecl->toChars());
        if (!fdecl->llvmValue)
            fdecl->llvmValue = LLVM_D_GetRuntimeFunction(gIR->module, fdecl->toChars());
        return;
    }

    bool declareOnly = false;
    bool templInst = fdecl->parent && DtoIsTemplateInstance(fdecl->parent);
    if (!templInst && fdecl->getModule() != gIR->dmodule)
        declareOnly = true;
    else if (fdecl->llvmInternal == LLVMva_start)
        declareOnly = true;

    if (!fdecl->llvmIRFunc) {
        fdecl->llvmIRFunc = new IRFunction(fdecl);
    }

    // mangled name
    char* mangled_name;
    if (fdecl->llvmInternal == LLVMintrinsic)
        mangled_name = fdecl->llvmInternal1;
    else
        mangled_name = fdecl->mangle();

    // unit test special handling
    if (fdecl->isUnitTestDeclaration())
    {
        assert(0 && "no unittests yet");
        /*const llvm::FunctionType* fnty = llvm::FunctionType::get(llvm::Type::VoidTy, std::vector<const llvm::Type*>(), false);
        // make the function
        llvm::Function* func = gIR->module->getFunction(mangled_name);
        if (func == 0)
            func = new llvm::Function(fnty,llvm::GlobalValue::InternalLinkage,mangled_name,gIR->module);
        func->setCallingConv(llvm::CallingConv::Fast);
        fdecl->llvmValue = func;
        return func;
        */
    }

    if (fdecl->llvmInternal == LLVMintrinsic && fdecl->fbody) {
        error("intrinsics cannot have function bodies");
        fatal();
    }

    llvm::Function* vafunc = 0;
    if ((fdecl->llvmInternal == LLVMva_start) || (fdecl->llvmInternal == LLVMva_intrinsic)) {
        vafunc = DtoDeclareVaFunction(fdecl);
    }

    Type* t = DtoDType(fdecl->type);
    TypeFunction* f = (TypeFunction*)t;

    // construct function
    const llvm::FunctionType* functype = DtoFunctionType(fdecl);
    llvm::Function* func = vafunc ? vafunc : gIR->module->getFunction(mangled_name);
    if (!func)
        func = new llvm::Function(functype, DtoLinkage(fdecl->protection, fdecl->storage_class), mangled_name, gIR->module);
    else
        assert(func->getFunctionType() == functype);

    // add func to IRFunc
    fdecl->llvmIRFunc->func = func;

    // calling convention
    if (!vafunc && fdecl->llvmInternal != LLVMintrinsic)
        func->setCallingConv(DtoCallingConv(f->linkage));

    // template instances should have weak linkage
    if (!vafunc && fdecl->llvmInternal != LLVMintrinsic && fdecl->parent && DtoIsTemplateInstance(fdecl->parent))
        func->setLinkage(llvm::GlobalValue::WeakLinkage);

    fdecl->llvmValue = func;
    assert(llvm::isa<llvm::FunctionType>(f->llvmType->get()));

    // main
    if (fdecl->isMain()) {
        gIR->mainFunc = func;
    }

    // static ctor
    if (fdecl->isStaticCtorDeclaration()) {
        gIR->ctors.push_back(fdecl);
    }
    // static dtor
    else if (fdecl->isStaticDtorDeclaration()) {
        gIR->dtors.push_back(fdecl);
    }

    // name parameters
    llvm::Function::arg_iterator iarg = func->arg_begin();
    int k = 0;
    if (f->llvmRetInPtr) {
        iarg->setName("retval");
        f->llvmRetArg = iarg;
        ++iarg;
    }
    if (f->llvmUsesThis) {
        iarg->setName("this");
        fdecl->llvmThisVar = iarg;
        assert(fdecl->llvmThisVar);
        ++iarg;
    }
    int varargs = -1;
    if (f->linkage == LINKd && f->varargs == 1)
        varargs = 0;
    for (; iarg != func->arg_end(); ++iarg)
    {
        Argument* arg = Argument::getNth(f->parameters, k++);
        //arg->llvmValue = iarg;
        //Logger::println("identifier: '%s' %p\n", arg->ident->toChars(), arg->ident);
        if (arg && arg->ident != 0) {
            if (arg->vardecl) {
                arg->vardecl->llvmValue = iarg;
            }
            iarg->setName(arg->ident->toChars());
        }
        else if (!arg && varargs >= 0) {
            if (varargs == 0) {
                iarg->setName("_arguments");
                fdecl->llvmArguments = iarg;
            }
            else if (varargs == 1) {
                iarg->setName("_argptr");
                fdecl->llvmArgPtr = iarg;
            }
            else
            assert(0);
            varargs++;
        }
        else {
            iarg->setName("unnamed");
        }
    }

    if (!declareOnly)
        gIR->defineList.push_back(fdecl);

    Logger::cout() << "func decl: " << *func << '\n';
}

//////////////////////////////////////////////////////////////////////////////////////////

// TODO split this monster up
void DtoDefineFunc(FuncDeclaration* fd)
{
    if (fd->llvmDefined) return;
    fd->llvmDefined = true;

    assert(fd->llvmDeclared);

    Logger::println("DtoDefineFunc(%s)", fd->toPrettyChars());
    LOG_SCOPE;

    // debug info
    if (global.params.symdebug) {
        Module* mo = fd->getModule();
        if (!mo->llvmCompileUnit) {
            mo->llvmCompileUnit = DtoDwarfCompileUnit(mo,false);
        }
        fd->llvmDwarfSubProgram = DtoDwarfSubProgram(fd, mo->llvmCompileUnit);
    }

    Type* t = DtoDType(fd->type);
    TypeFunction* f = (TypeFunction*)t;

    assert(f->llvmType);
    llvm::Function* func = fd->llvmIRFunc->func;
    const llvm::FunctionType* functype = func->getFunctionType();

    // only members of the current module or template instances maybe be defined
    if (fd->getModule() == gIR->dmodule || DtoIsTemplateInstance(fd->parent))
    {
        fd->llvmDModule = gIR->dmodule;

        // function definition
        if (fd->fbody != 0)
        {
            Logger::println("Doing function body for: %s", fd->toChars());
            assert(fd->llvmIRFunc);
            gIR->functions.push_back(fd->llvmIRFunc);

            if (fd->isMain())
                gIR->emitMain = true;

            llvm::BasicBlock* beginbb = new llvm::BasicBlock("entry",func);
            llvm::BasicBlock* endbb = new llvm::BasicBlock("endentry",func);

            //assert(gIR->scopes.empty());
            gIR->scopes.push_back(IRScope(beginbb, endbb));

                // create alloca point
                f->llvmAllocaPoint = new llvm::BitCastInst(llvm::ConstantInt::get(llvm::Type::Int32Ty,0,false),llvm::Type::Int32Ty,"alloca point",gIR->scopebb());
                gIR->func()->allocapoint = f->llvmAllocaPoint;

                // need result variable? (not nested)
                if (fd->vresult && !fd->vresult->nestedref) {
                    Logger::println("non-nested vresult value");
                    fd->vresult->llvmValue = new llvm::AllocaInst(DtoType(fd->vresult->type),"function_vresult",f->llvmAllocaPoint);
                }

                // give arguments storage
                size_t n = Argument::dim(f->parameters);
                for (int i=0; i < n; ++i) {
                    Argument* arg = Argument::getNth(f->parameters, i);
                    if (arg && arg->vardecl) {
                        VarDeclaration* vd = arg->vardecl;
                        if (!vd->llvmNeedsStorage || vd->nestedref || vd->isRef() || vd->isOut() || DtoIsPassedByRef(vd->type))
                            continue;
                        llvm::Value* a = vd->llvmValue;
                        assert(a);
                        std::string s(a->getName());
                        Logger::println("giving argument '%s' storage", s.c_str());
                        s.append("_storage");
                        llvm::Value* v = new llvm::AllocaInst(a->getType(),s,f->llvmAllocaPoint);
                        gIR->ir->CreateStore(a,v);
                        vd->llvmValue = v;
                    }
                    else {
                        Logger::attention("some unknown argument: %s", arg ? arg->toChars() : 0);
                    }
                }

                // debug info
                if (global.params.symdebug) DtoDwarfFuncStart(fd);

                llvm::Value* parentNested = NULL;
                if (FuncDeclaration* fd2 = fd->toParent()->isFuncDeclaration()) {
                    if (!fd->isStatic())
                        parentNested = fd2->llvmNested;
                }

                // need result variable? (nested)
                if (fd->vresult && fd->vresult->nestedref) {
                    Logger::println("nested vresult value: %s", fd->vresult->toChars());
                    fd->llvmNestedVars.insert(fd->vresult);
                }

                // construct nested variables struct
                if (!fd->llvmNestedVars.empty() || parentNested) {
                    std::vector<const llvm::Type*> nestTypes;
                    int j = 0;
                    if (parentNested) {
                        nestTypes.push_back(parentNested->getType());
                        j++;
                    }
                    for (std::set<VarDeclaration*>::iterator i=fd->llvmNestedVars.begin(); i!=fd->llvmNestedVars.end(); ++i) {
                        VarDeclaration* vd = *i;
                        vd->llvmNestedIndex = j++;
                        if (vd->isParameter()) {
                            assert(vd->llvmValue);
                            nestTypes.push_back(vd->llvmValue->getType());
                        }
                        else {
                            nestTypes.push_back(DtoType(vd->type));
                        }
                    }
                    const llvm::StructType* nestSType = llvm::StructType::get(nestTypes);
                    Logger::cout() << "nested var struct has type:" << '\n' << *nestSType;
                    fd->llvmNested = new llvm::AllocaInst(nestSType,"nestedvars",f->llvmAllocaPoint);
                    if (parentNested) {
                        assert(fd->llvmThisVar);
                        llvm::Value* ptr = gIR->ir->CreateBitCast(fd->llvmThisVar, parentNested->getType(), "tmp");
                        gIR->ir->CreateStore(ptr, DtoGEPi(fd->llvmNested, 0,0, "tmp"));
                    }
                    for (std::set<VarDeclaration*>::iterator i=fd->llvmNestedVars.begin(); i!=fd->llvmNestedVars.end(); ++i) {
                        VarDeclaration* vd = *i;
                        if (vd->isParameter()) {
                            gIR->ir->CreateStore(vd->llvmValue, DtoGEPi(fd->llvmNested, 0, vd->llvmNestedIndex, "tmp"));
                            vd->llvmValue = fd->llvmNested;
                        }
                    }
                }

                // copy _argptr to a memory location
                if (f->linkage == LINKd && f->varargs == 1)
                {
                    llvm::Value* argptrmem = new llvm::AllocaInst(fd->llvmArgPtr->getType(), "_argptrmem", gIR->topallocapoint());
                    new llvm::StoreInst(fd->llvmArgPtr, argptrmem, gIR->scopebb());
                    fd->llvmArgPtr = argptrmem;
                }

                // output function body
                fd->fbody->toIR(gIR);

                // llvm requires all basic blocks to end with a TerminatorInst but DMD does not put a return statement
                // in automatically, so we do it here.
                if (!fd->isMain()) {
                    if (!gIR->scopereturned()) {
                        // pass the previous block into this block
                        if (global.params.symdebug) DtoDwarfFuncEnd(fd);
                        if (func->getReturnType() == llvm::Type::VoidTy) {
                            new llvm::ReturnInst(gIR->scopebb());
                        }
                        else {
                            new llvm::ReturnInst(llvm::UndefValue::get(func->getReturnType()), gIR->scopebb());
                        }
                    }
                }

                // erase alloca point
                f->llvmAllocaPoint->eraseFromParent();
                f->llvmAllocaPoint = 0;
                gIR->func()->allocapoint = 0;

            gIR->scopes.pop_back();

            // get rid of the endentry block, it's never used
            assert(!func->getBasicBlockList().empty());
            func->getBasicBlockList().pop_back();

            // if the last block is empty now, it must be unreachable or it's a bug somewhere else
            // would be nice to figure out how to assert that this is correct
            llvm::BasicBlock* lastbb = &func->getBasicBlockList().back();
            if (lastbb->empty()) {
                if (lastbb->getNumUses() == 0)
                    lastbb->eraseFromParent();
                else {
                    new llvm::UnreachableInst(lastbb);
                    /*if (func->getReturnType() == llvm::Type::VoidTy) {
                        new llvm::ReturnInst(lastbb);
                    }
                    else {
                        new llvm::ReturnInst(llvm::UndefValue::get(func->getReturnType()), lastbb);
                    }*/
                }
            }

            gIR->functions.pop_back();
        }
    }
}

//////////////////////////////////////////////////////////////////////////////////////////

void DtoMain()
{
    // emit main function llvm style
    // int main(int argc, char**argv, char**env);

    assert(gIR != 0);
    IRState& ir = *gIR;

    assert(ir.emitMain && ir.mainFunc);

    // parameter types
    std::vector<const llvm::Type*> pvec;
    pvec.push_back((const llvm::Type*)llvm::Type::Int32Ty);
    const llvm::Type* chPtrType = (const llvm::Type*)llvm::PointerType::get(llvm::Type::Int8Ty);
    pvec.push_back((const llvm::Type*)llvm::PointerType::get(chPtrType));
    pvec.push_back((const llvm::Type*)llvm::PointerType::get(chPtrType));
    const llvm::Type* rettype = (const llvm::Type*)llvm::Type::Int32Ty;

    llvm::FunctionType* functype = llvm::FunctionType::get(rettype, pvec, false);
    llvm::Function* func = new llvm::Function(functype,llvm::GlobalValue::ExternalLinkage,"main",ir.module);

    llvm::BasicBlock* bb = new llvm::BasicBlock("entry",func);

    // call static ctors
    llvm::Function* fn = LLVM_D_GetRuntimeFunction(ir.module,"_moduleCtor");
    llvm::Instruction* apt = new llvm::CallInst(fn,"",bb);

    // call user main function
    const llvm::FunctionType* mainty = ir.mainFunc->getFunctionType();
    llvm::CallInst* call;
    if (mainty->getNumParams() > 0)
    {
        // main with arguments
        assert(mainty->getNumParams() == 1);
        std::vector<llvm::Value*> args;
        llvm::Function* mfn = LLVM_D_GetRuntimeFunction(ir.module,"_d_main_args");

        llvm::Function::arg_iterator argi = func->arg_begin();
        args.push_back(argi++);
        args.push_back(argi++);

        const llvm::Type* at = mainty->getParamType(0)->getContainedType(0);
        llvm::Value* arr = new llvm::AllocaInst(at->getContainedType(1)->getContainedType(0), func->arg_begin(), "argstorage", apt);
        llvm::Value* a = new llvm::AllocaInst(at, "argarray", apt);
        llvm::Value* ptr = DtoGEPi(a,0,0,"tmp",bb);
        llvm::Value* v = args[0];
        if (v->getType() != DtoSize_t())
            v = new llvm::ZExtInst(v, DtoSize_t(), "tmp", bb);
        new llvm::StoreInst(v,ptr,bb);
        ptr = DtoGEPi(a,0,1,"tmp",bb);
        new llvm::StoreInst(arr,ptr,bb);
        args.push_back(a);
        new llvm::CallInst(mfn, args.begin(), args.end(), "", bb);
        call = new llvm::CallInst(ir.mainFunc,a,"ret",bb);
    }
    else
    {
        // main with no arguments
        call = new llvm::CallInst(ir.mainFunc,"ret",bb);
    }
    call->setCallingConv(ir.mainFunc->getCallingConv());

    // call static dtors
    fn = LLVM_D_GetRuntimeFunction(ir.module,"_moduleDtor");
    new llvm::CallInst(fn,"",bb);

    // return
    new llvm::ReturnInst(call,bb);
}

//////////////////////////////////////////////////////////////////////////////////////////

const llvm::FunctionType* DtoBaseFunctionType(FuncDeclaration* fdecl)
{
    Dsymbol* parent = fdecl->toParent();
    ClassDeclaration* cd = parent->isClassDeclaration();
    assert(cd);

    FuncDeclaration* f = fdecl;

    while (cd)
    {
        ClassDeclaration* base = cd->baseClass;
        if (!base)
            break;
        FuncDeclaration* f2 = base->findFunc(fdecl->ident, (TypeFunction*)fdecl->type);
        if (f2) {
            f = f2;
            cd = base;
        }
        else
            break;
    }

    DtoResolveDsymbol(f);
    return llvm::cast<llvm::FunctionType>(DtoType(f->type));
}

//////////////////////////////////////////////////////////////////////////////////////////